Maine is the state with the most complex border with Canada. The line begins in the Atlantic Ocean and follows rivers, streams, mountain ridges, and straight lines, for 611 miles, and through 24 manned border crossings, more than any other state. A dozen rail bridges and dams cross the line, and even paper plants span the border, in a state so dominated by wood-products industries. The International Boundary along Maine’s eastern edge goes through Passamaquoddy Bay, up the St. Croix River, through flooded lakes, up a small creek, then along the North Line to the St. John River, near the top of the state. This first, watery portion of the border was defined by the Treaty of Paris, in 1783, the treaty that ended the war with Great Britain. It describes the northern border of the USA, from the Atlantic to Prairies, as from the “mouth of the St. Croix River to the northwesternmost point of the Lake of the Woods,” in which is now western Minnesota. Soon afterwards, the Jay Treaty of 1794 was convened to establish just what the “St. Croix River” was, as the name was drawn from a vague seventeenth century map, drawn by a European, and nobody really referred to any specific river around here by that name. This was settled by actually finding the remains of Samuel Champlain’s camp on the river, built when he first visited in 1604. The 1814 Treaty of Ghent settled disputes over the islands in Passamaquoddy Bay, establishing the route of the boundary through those waters, and mandated that the border would extend from the “source of the St. Croix River” as a straight line due north to the “northwest angle of Nova Scotia,” a location which would lead to some dispute later on (the Aroostook War), eventually resolved by the Webster Ashburton Treaty of 1842, as the St. John River, which now defines the border for much of northern Maine.

4697 Google map.

3991 Google map.The eastern end of the international boundary between the USA and Canada begins with uncertainty, ten miles off the coast, at Machais Seal Island, a 20-acre treeless outcrop which is still claimed by both nations. The British built a lighthouse on the island in 1832, claiming it for Nova Scotia, and the Canadian government, which has since automated all the other lighthouses along their coast, keeps this one staffed for the purpose of making a claim for continuous occupation and sovereignty. The USA also claims the island, and a commercial tour operator brings birdwatchers to the island from the coast of Maine. For the moment, without any resources other than the lobsters in the fishery “grey zone” around the island, there has not been any reason to fight over the island. Both nations think of it as theirs. Though there are a few other remaining boundary disputes between the USA and Canada, concerning coastal waters and their respective Exclusive Economic Zones on the west coast, this is the only remaining unsettled boundary dispute over dry land. The island, at the gateway to the longest international boundary in the world, is a borderless space.

3800 Google map.From the east, the International Boundary comes towards the shore, passes by West Quoddy Head, the easternmost point of land in the USA, and enters the interior waters of the continent at Lubec Channel and Passamaquoddy Bay.

3996 CLUI photo.There is a lighthouse on West Quoddy Head, with a foghorn, as these rocky shores are often completely shrouded in mist.

3997 CLUI photo.The lighthouse is the easternmost building in the USA.

3998 CLUI photo.Some rocks extending eastward on the shore are the actual easternmost point.

3999 CLUI photo.The easternmost gift shop in the USA is nearby.

3801 Google map.After passing West Quoddy Head the boundary line enters Lubec Channel and Passamaquoddy Bay.

3995 CLUI photo.The first physical structure encountered by the boundary is the Franklin Delano Roosevelt Bridge, which connects the town of Lubec, Maine, and Campobello Island, part of New Brunswick, Canada. Campobello is a kind of an exclave of Canada, an island connected by land only to the USA, by this bridge. There is a customs and immigration port of entry building on either side of the bridge, the easternmost of the 24 official border crossing points in the state, and the 115 along the line between the east and west coasts.

4000 CLUI photo.The island has a visitor center for the Roosevelt Campobello International Park, one of the few parks in the world administered jointly by two national governments. Inside is a gift shop and a small bilingual display about the openness of the border. The park exists because Franklin Roosevelt, the former president of the United States, had a summer home here, which he came to mostly as a child. As president he only stayed overnight here once.

4001 CLUI photo.Originally built by the Kuhn family of Boston, the 34-room Roosevelt “cottage” was later owned by Armand Hammer, the head of Occidental Petroleum, who continued to allow Eleanor Roosevelt to visit until 1963, when it became a park.

4002 CLUI photo.The easternmost manifestation of the USA/Canada boundary line itself is the plaque (with the change in paint color), in the middle of the Lubec/Campobello bridge.

4003 CLUI photo.At the other end of the bridge is the small community of Lubec, Maine, the easternmost town in the United States. There is a small downtown, a hotel, and a boat ramp at a small fishing harbor.

4004 CLUI photo.The boundary runs past town through Lubec Narrows, with a breakwater on the USA side, and a lighthouse on the Canadian side.

3993 CLUI photo.A Range Marker on the breakwater marks the course of the international boundary, which makes a turn to the northeast after passing through the narrows.These markers, located on shore and on nautical charts, can be lined up to help boaters know where they are in relation to the border. Boats can cross the watery boundary without getting into trouble, so long as they check in with customs and immigration if they land in the other country. But fishermen and lobstermen need to know where the boundary is, so they don’t catch fish from the other side of the line.

3994 CLUI photo.The Range Marker on the breakwater lines up with another on shore, forming a line that defines the border for one stretch over the water.

3825 Google map.North of Lubec, the zig-zagging water boundary enters the Friar Roads portion of Passamaquoddy Bay, and approaches Moose Island, home of the city of Eastport, Maine, the easternmost city in the USA (because Lubec, though slightly further east is officially a town, not a city). After the war of 1812, the island was claimed by the British, who believed it to be on their side of the water boundary. They returned it to the United States in 1818, making this the “last place in the country occupied by a foreign nation,” besides the two islands in Alaska occupied by the Japanese in World War II.

4005 CLUI photo.In 1833, Eastport was the second largest trading port in the USA, after New York City. Today it is a small and run down village with old brick storefronts that are slowly being restored, by organizations such as the Tides Institute, which operates a residence program and a gallery downtown.

4006 CLUI photo.


3826 Google map.Eastport’s Moose Island is connected now to the mainland by causeways that travel through the Point Pleasant Passamaquoddy Indian Reservation. The Jay Treaty of 1794 allowed natives to freely travel between their territory on either side of the newly established international boundary. But because the tribe is not recognized by Canada, the local Indians here are not permitted to land on the other side of the bay without reporting to customs.

4007 CLUI photo.

3827 Google map.North of Point Pleasant, the international boundary heads north northwest through Passamaquoddy Bay, and into the channel of the St. Croix River. Along the way, it crosses the 45th Parallel, the halfway point between the Equator and the North Pole.

3828 Google map.In the middle of the channel is St. Croix Island, where French colonialists, including the explorer Samuel Champlain, landed and wintered in 1604. This was the earliest European settlement in what is now the USA, north of Florida (where the village of St. Augustine was founded by the Spanish in 1565).

4054 CLUI photo.Champlain went on to establish Quebec in 1608, and is considered one of the founders of what would become Canada. Since this was where he first arrived in the new world, many think of it as the “birthplace of Canada” even though now it is in the United States.

4055 CLUI photo.The settlement built there was burned down by English raiders on their way to Nova Scotia, in 1613. The seven-acre island became a US National Monument in 1949, and is administered by the US National Park Service.

4056 CLUI photo.Though there are public interpretive facilities on shore, the island itself remains off-limits to the public, to protect the historic remains buried there and eroding into the river.

3829 Google map.North of St. Croix Island, the river channel narrows, and turns westward towards the community of Calais, Maine. With the city of St. Stephen, New Brunswick, on the other side of the river, Calais is a true border town, a community of nearly 10,000 people, divided by the international boundary which follows the middle of the river channel.

3830 Google map.

4008 CLUI photo.There are three road crossings connecting the two cities, each with customs and immigration Ports of Entry on either side of the bridge. The Ferry Point Bridge connects the two downtowns. Nearby, a park on the US side has interpretive plaques that describe the importance of the community as a logging industry shipping center, using the river, throughout the nineteenth century, and in to the 20th. Upstream the river has a few rapids, which is why the town developed here. Dams were built on the rapids, spanning the international boundary, to capture energy for the mills, and flatten the water, for floating logs.

3831 Google map.The Milltown Bridge is the second road crossing the river and the boundary. It is a very small crossing, used by locals, and no commercial traffic.

3867 Google map.The third and busiest crossing is the International Avenue Bridge, on the west end of town, where, on the Canadian side, a divided highway has been built connecting Calais to the big New Brunswick city of St. John, and to the Trans-Canada Highway. This new commercial crossing opened in 2009, and was the first new crossing between the two countries to be built in more than 35 years.

3832 Google map.Upstream of Calais, the river and the border bends southwest, then northwest. The boundary was originally described as the middle of the channel, but by 1909, was changed to the line following the deepest point of the main channel, known as the thalweg.

3833 Google map.Whether following land or water, the border is made up of thousands of straight lines, with logged turning points at either end. On water these points are referenced by survey markers on shore, set by the International Boundary Commission.

4009 CLUI photo.The next physical crossing of the river/international boundary is a dam that provides power and water for the adjacent pulp and paper plant at the town of Woodland, which opened in 1906, providing paper for the Boston Globe.

3866 Google map.North of the plant a major utility right of way crosses the river and the international boundary, where gas and electric lines come in from the Canadian side. This part of Maine is remote, and off the ISO New England grid, so most of eastern Maine gets its electricity from Canadian sources, such as New Brunswick Power, and Hydro Quebec, or from small hydro plants built along the rivers.

4045 CLUI photo.A little further upstream is the Grand Falls Dam and power plant, built by the Woodland paper company in 1915, on top of a former waterfall. The border runs through the edge of the Dam.

4010 CLUI photo.Hydro stations like this provide energy primarily for their builders, the local paper plants.

4011 CLUI photo.Paper company dams throughout the state make flooded valleys of artificial lakes and widened rivers called flowage, used for floating logs, and providing power.

3834 Google map.Most of the lakes in Maine are artificial byproducts of the paper industry.

3835 Google map.The international boundary continues north through the flowage, following the now flooded St. Croix River through remote logging country, until the next border crossing, the old rail bridge at Vanceboro, Maine.

3836 Google map.The bridge was on an important line connecting the northeastern USA and the Maritimes, from 1871 to the early 20th century. 

4046 CLUI photo.In 1915 the bridge was bombed by a German spy, attempting to limit routes for troops that he suspected might be coming through Canada to fight the Germans (as the US was still neutral in World War 1, at that time). The spy was caught, convicted, and after serving six years in prison, was finally considered insane, and sent back to Germany. The bridge, though quickly repaired after the bombing, fell into disuse over the following years, with more expedient shipping methods and routes, roads and rail, developed through the region.

4012 CLUI photo.North of the bridge, the river boundary heads through the small remote town of Vanceboro, passing under a road bridge, with a Port of Entry on either side, known as the Vanceboro/Ste. Croix crossing.

4013 CLUI photo.Upstream of it the boundary line passes through the middle of the Vanceboro Dam, and into the lake on the other side.

3837 Google map.The boundary zigs and zags invisibly over the open water of the lake, following the original river channel, now flooded by the flowage, known as the Chiputneticook Lakes.

4014 CLUI photo.The lakes extend northward for 25 miles, until the small remote community of Forest City, and the next official border crossing, on a road over the river.

3838 Google map.In 2010, US Homeland Security proposed upgrading their current Port of Entry here with a new $15 million facility, with detention cells and an impound lot. All for a port that averages less than seven cars per day, and is open from 8am to 4pm. Media attention, including coverage by John Stossel’s “Gimme a Break!” TV program, caused a rethink.

3839 Google map.Instead, after some delay, a new $5.4 million facility opened in 2012.

3840 Google map.The international boundary follows the river past the new Port of Entry, through the Grand Lake Dam, at the west end of town, and through the middle of the lake, to its northern end, where there is another bridge and border crossing.

4015 CLUI photo.This, the Orient/Fosterville crossing, on Boundary Road, between Orient, Maine, and Fosterville, New Brunswick, open 8am-midnight, is the last border crossing over the St. Croix River.

3841 Google map.From here the boundary follows Monument Brook, considered the headwaters of the St. Croix, with its increasingly minute meanders through the remote forest, towards its origin a wooded swamp.

3842 Google map.In the middle of the swamp is a tall stone obelisk, known as Monument 1, installed in 1843, to mark the source of the St. Croix. Traveling the boundary from east to west, Monument 1 is the first dry land monument, marking the border exactly on the ground. Up to this point, the boundary has been over water, and though the turning points of the boundary are referenced by survey monuments on shore, the only markers on the line itself have been plaques on bridges.

4047 CLUI photo.Though it is a functional survey point, Monument 1 is an ornamental monument, larger than most boundary monuments, because of its significance as the first land monument on the east end of the border. It is one of only five such monumental monuments on the line. There is another at the west end of the boundary, on a bluff overlooking the Pacific Ocean, 3,500 miles down the line.

3864 Google map.Monument 1 marks both the source of the St. Croix, and the southern end of the “North Line” portion of the boundary, a straight line running north from the monument, over hill and dale, until it hits the middle of the St. John River, 78 miles away.

4027 CLUI photo.The North Line has around 230 monuments along its path, each marked by one or more nearby and less prominent reference markers. To maintain visibility along the border as it travels over land, a swath is cut through the trees and brush, for a distance of ten feet on either side of the boundary. This results in a 20-foot wide clearing known as a cut line.

4048 CLUI photo.The line is also known as the vista line, as its function is to make the boundary visible, so people don’t accidentally cross it. This vista line is maintained by the International Boundary Commission, and its upkeep and condition depends on the priorities and limited resources of the commission. The IBC, with a US and Canadian Commissioner, also maintains the border monuments, of which there are more than 8,000 across the line.

3843 Google map.A few miles north of Monument 1, a road from the USA side curves southward and travels directly on the boundary for nearly a mile, next to a field in Canada.

4028 CLUI photo.There are a couple of steel monuments marking line on the side of the road, but the road and the field serve as the vista line.

4029 CLUI photo.Along the road is a former USA Port of Entry building.

4030 CLUI photo.This once was the East Hodgdon/Union Corners crossing, one of half a dozen manned crossings that have been permanently closed along the North Line since the late 1950s.

4031 CLUI photo.The Port of Entry building was sold off, and became a private home that has since been abandoned.

4016 CLUI photo.As is typical, and usually the case, the open space is monitored by powerful cameras mounted on poles, along with movement sensors that alert the Border Patrol, watching the system from a regional field station. Once triggered, the cameras begin recording, and can be zoomed in on suspects to see if anyone crosses the line, or moves any goods over it. If so, they have documentation, and they can dispatch the nearest agent to the scene.

4017 CLUI photo.There are thousands of these pole-mounted cameras along the border, and dozens of regional Border Patrol field stations. Of the 60,000 employees of the Customs and Border Protection division of the Department of Homeland Security, which operates the Ports of Entry, and includes the Border Patrol, around 5,000 work the USA/Canada boundary (more work the USA/Mexico boundary). The Canadian RCMP also operate cameras on the line, and share information with their US counterparts.

3844 Google map.The first official and open crossing on the North Line is a few miles further north, at Houlton, Maine.

4018 CLUI photo.This is the north end of Interstate 95, the principal Interstate of the East Coast, extending south to Florida. 

4019 CLUI photo.When they opened the Interstate in the 1970s, they abandoned the old Port of Entry building and closed the two-lane highway next to it, diverting traffic onto the Interstate, with its new and larger Port of Entry.

4020 CLUI photo.The road surface at the old crossing has a mound of dirt piled on the actual borderline.

4049 CLUI photo.The building itself has peeling paint and old furniture still inside, forty years later.

4021 CLUI photo.A time capsule of the old style of border crossings.

4022 CLUI photo.Nearby is another relic in Houlton, the former Army airport, where German POWs were kept in World War Two.

4023 CLUI photo.The ruins of the camp is in the woods, against the border, next to a police shooting range, and a fire department training area. It is common to find these kinds of land uses pushed out of the way, to the extreme margins of the country.

3845 Google map.A few miles further up the North Line is another closed crossing, Starkey’s Corners, on Foxcroft Road east of Littleton. The paved road is blocked at the borderline, and the Port of Entry is now a private home.

3846 Google map.The Monitcello/Bloomfield crossing is a few miles north of Starkey’s Corner, and is still open, though it has limited hours, is closed on Sundays, and the gates are shut when no one is there. 

3847 Google map.A few miles further north is the Bridgewater/Centreville crossing, which is open around the clock, every day.

4032 CLUI photo.After that the North Line continues north, passing behind Mars Hill, a prominent landmark, and a ski area, topped by a wind farm.

4024 CLUI photo.This is potato farming country, where several large processing plants bag, cut, and freeze the product for nationwide distribution.

4025 CLUI photo.A few miles west of the boundary, near Spragueville, is where the Double Eagle II hot air balloon took off for its historic flight in 1978, when it became the first hot air balloon to cross the Atlantic.

4026 CLUI photo.The northeastern edge of the nation, closer to Europe and Russia, is a strategic location for military aviation as well. In the 1960s, nearby Presque Isle Airport was a Strategic Air Command base, with Snark nuclear missiles pointed at Russia.

3848 Google map.North of Mars Hill is another formerly manned border crossing, on East Ridge Road. The US Port of Entry, operated out of a trailer before it closed in 1976. The Canadian Port of Entry is still there, now a private home. The road is blocked with a barricade.

3849 Google map.The next open crossing on the North Line is the Easton/River de Chute crossing, on Smugglers Road, which is open every day, but has limited hours. Gates block the road when it is closed. It has round 4,000 crossing a year, an average of less than 11 per day.

3850 Google map.A few miles further up the North Line is the busier Fort Fairfield/Perth-Andover crossing, which is open continuously, and is a rare example of a crossing where the Canadian Port of Entry building is larger than the US one. There is a road that heads south, between the Ports of Entry, on the US side, with some homes on the Canadian side, which are only accessible by the road on the US side of the line. Leaving the driveway, or coming home, is thus an international trip. Since they have to pass through either of the Ports of Entry to get anywhere else though, they are not too inconvenienced (unless there is a line at the Port). And since the access road is between the ports, they don’t have to pass the Port of Entry when returning home, from either direction, even though, technically, they might have goods to declare, such as groceries. 

3851 Google map.This condition occurs at a number of places along the border, and though it can be very inconvenient for the residents (sometimes referred to as “’tweenies,” by border officials, as they live between the Ports of Entry), generally they are known to the officials, their car is recognized, and in some cases they are trusted enough not to have to stop, if they are just making a quick trip to town.

3852 Google map.North of Fairfield the boundary line passes through the Aroostook River.

3853 Google map.On the southern shore is the former Aroostook Falls crossing. It was barricaded and permanently closed in 1994, after the river flooded and killed two Canadian customs agents who were trapped in their car.

3854 Google map.On the north side of the river is the Aroostook Valley Country Club, with a golf course on the New Brunswick side, mostly - a truly international “country club.”

3855 Google map.The parking lot for the club is in the USA, but most of the buildings are in Canada, including the club house.

4057 CLUI photo.The course was built in the late 1920s, during prohibition, likely why the club house was placed in Canada.

4050 CLUI photo.The pro shop, however, sits, just barely, on the US side of the line, easing transactions, both wholesale and retail, at least for the American suppliers and members of the club.

4058 CLUI photo.Most of the course itself is in Canada, but part of the tee area for the par four ninth hole is in the US.

4059 CLUI photo.And possibly part of a sand trap on the first hole, perhaps the world's only international sand trap.

4061 CLUI photo.The Boundary Commission has asked that a row of trees on the edge of the course be replaced, as they block the vista line. The club may remove them when a new row, planted outside the 20 foot wide boundary zone, matures sufficiently.

4060 CLUI photo.In the old days visitors to the club from either country came and went on back roads without reporting to Customs and Immigration. After 9/11, things along the border tightened up. Visitors to the club coming from Canada must now travel through manned Ports of Entry, several miles away, and follow normal procedures.

4052 CLUI photo.Since access to the club is through roads on the US side, American visitors do not have to report, even though they may spend the day golfing and drinking in Canada. The golf club is one of the gray zones on the border, where, in a sense, US territory extends into Canada.

4062 CLUI photo.Russell Road, the road heading north on the border from the club, curves east into Canada, and used to be the most direct route for Canadian visitors to the club. But the road has no Port of Entry on the US side (it closed in the 1960s), effectively, but not physically closing the road to US-bound traffic.

4043 CLUI photo.Strong warning signs, with threats of arrest, try to keep people away, though by the time you are close enough to read the signs, you have already transgressed.

4042 CLUI photo.A trailer serves as a temporary Canadian Port of Entry, known as Four Falls, open mostly during the summer season to make it easier for Canadian golfers to go home.  For anybody who approaches the trailer from the US side to discover that it is closed, or who decide they don’t want to enter Canada afterall, turning around seems like a good option. However since you have already crossed the line to get to the trailer, even though only by a few yards, technically you have to drive to the nearest manned US Port of Entry and report your re-entry into the nation.

4041 CLUI photo.Either way, your visit will have been recorded by the video cameras trained on the road, so your actions can be verified. But mostly people just turn around and head back to the USA, without incident.

4040 CLUI photo.The international imbalance of boundary enforcement along Russell Road has been especially hard on the Pedersen Family, who lived on the road since 1950, and whose driveway is in the USA, but whose house is in Canada.

3856 Google map.For half a century this wasn’t a problem, and officials let them come and go, as if they lived in the USA. In 2003, the elderly owners were threatened with arrest by US Border Patrol, simply for pulling out of their driveway. Some say acrimony developed because the owners were opposing a road that the country club and border officials wanted to build through their back field, to provide access through Canada to the country club. Either way, though some concessions were eventually made, visitors and family members had a hard time negotiating the newly enforced rules, and having to drive up to 15 miles out of their way to go through the Port of Entry. The house has recently been abandoned, and its future is uncertain.

3857 Google map.The North Line continues northward from the Pedersen’s house, cutting its swath across farmland, woods, and streams for another eight miles, to the next official crossing, Limestone/Gillespie-Portage, a small crossing on Highway 229.

3858 Google map.South of the small crossing is a former Nike Missile launch site, a hundred yards from the border.

4038 CLUI photo.The facility has been turned into a car repair business, and home, with old vehicles and equipment covering the former launch pad.

4039 CLUI photo.This was one of four Nike Missile stations protecting Loring Air Force Base, located nearby in Limestone.

3859 Google map.Loring was a major Strategic Air Command base, with heavy bombers based out of there in continuous flight, ready to bomb Russia at a moment's notice.

4035 CLUI photo.The base ceased most operations in 1994, but some reserve and military operations continue there.

4037 CLUI photo.The rest of the base is mostly unused, and is disrepair. Empty buildings include hangars capable of holding six B-52s at once.

3860 Google map.The nuclear weapons assembly and storage area, known as the North River Depot, was emptied, but remains off limits to the public.

4036 CLUI photo.Loring is another example of how defensive (and offensive) installations developed along the northern edges of the country, to be that much closer to the rest of the world.

3861 Google map.The North Line continues north for another ten miles.

4053 CLUI photo.Up to the Hamlin/Grand Falls crossing, on Boundary Road, next to the St. John River.

3862 Google map.After passing through the crossing, and Monument 117, on the shore, the North Line hits the water, and ends, midstream.

3863 Google map.From here, it heads west along the center of the channel of the St. John River. The boundary is, again, a water boundary, at least for the next 100 miles.