Yukon Territory

The border of Yukon begins at the Beaufort Sea at 69°39′N 141°00′W / 69.650°N 141.000°W / 69.650; -141.000 and proceeds southwards along the 141st meridian west. At 60°18′N, the border proceeds away from the 141st meridian west in a southeastward direction, following the St. Elias Mountains. South of the 60th parallel north, the border continues into British Columbia. The entire Canada–U.S. border in Yukon is shared with the U.S. state of Alaska.

British Columbia

British Columbia has two international borders with the United States: with the state of Alaska along BC's northwest, and with the contiguous United States along the southern edge of the province.

The former, continuing from the Yukon-Alaska border, proceeds through the St. Elias Mountains, followed by Mt. Fairweather at 58°54′N 137°31′W / 58.900°N 137.517°W / 58.900; -137.517, where the border heads northwestward towards the Coast Mountains. At 59°48′N 135°28′W / 59.800°N 135.467°W / 59.800; -135.467, the border begins a general southeastward direction along the Coast Mountains. The border eventually reaches the Portland Canal and follows it outward to the Dixon Entrance, which takes the border down and out into the Pacific Ocean, terminating it upon reaching international waters.

BC's border along the contiguous US begins southwest of Vancouver Island and northwest of the Olympic Peninsula, at the terminus of international waters in the Pacific Ocean. It follows the Strait of Juan de Fuca eastward, turning northeastward to enter Haro Strait. The border follows the strait in a northward direction, but turns sharply eastward through Boundary Pass, separating the Canadian Gulf Islands from the American San Juan Islands. Upon reaching the Strait of Georgia, the border turns due north and then towards the northwest, bisecting the strait until the 49th parallel north. After making a sharp turn eastbound, the border follows this parallel across the Tsawwassen Peninsula, separating Point Roberts, Washington from Delta, British Columbia, and continues into Alberta. From west to east, BC's southern border is shared with the U.S. states of Washington, Idaho, and Montana.

Alberta

The entire Canada–U.S. border in the Canadian province of Alberta lies on the 49th parallel north. From west to east, this border is shared only with the U.S. state of Montana.

Saskatchewan

The entire Canada–U.S. border in the Canadian province of Saskatchewan lies on the 49th parallel north. From west to east, this border is shared with the U.S. states of Montana and North Dakota.

Manitoba

Nearly the entire Canada–U.S. border in the province of Manitoba lies on the 49th parallel north. At the province's eastern end, however, the border briefly enters the Lake of the Woods, turning north at 48°59′N 95°09′W / 48.983°N 95.150°W / 48.983; -95.150 where it continues into land along the western end of Minnesota's Northwest Angle, reaching Ontario at 49°23′N 95°09′W / 49.383°N 95.150°W / 49.383; -95.150. From west to east, this border is shared with the U.S. states of North Dakota and Minnesota.

Ontario

The Ontario border begins at the northwesternmost point of Minnesota's Northwest Angle (49°23′N 95°09′W / 49.383°N 95.150°W / 49.383; -95.150), from where it proceeds eastward through the Angle Inlet into the Lake of the Woods. At 41°19′N 94°48′W / 41.317°N 94.800°W / 41.317; -94.800 into the Lake, the border turns southward where it continues into the Rainy River. The border follows the River to Rainy Lake, then subsequently through various smaller lakes, including Namakan Lake, Lac la Croix, and Sea Gull Lake, until it reaches the Pigeon River, which leads it out into Lake Superior. The border continues through Lake Superior and Whitefish Bay, into the St. Mary's River then the North Channel. At 45°59′N 83°26′W / 45.983°N 83.433°W / 45.983; -83.433, the border turns southward into the False Detour Channel, from which it reaches Lake Huron. Through the Lake, the border heads southward until reaching the St. Clair River, leading it to Lake St. Clair. The border proceeds through Lake St. Clair, reaching the Detroit River, which leads it to Lake Erie. From Lake Erie the border is lead into the Niagara River, which takes it into Lake Ontario. From here, the boundary heads northwestward until it reaches 43°27′N 79°12′W / 43.450°N 79.200°W / 43.450; -79.200, where it makes a sharp turn towards the northeast. The border then reaches the St. Lawrence River, proceeding through it until finally, at 45°00′N 74°40′E / 45.000°N 74.667°E / 45.000; 74.667, the border splits from the River and continues into Quebec. From west to east, this border is shared with the U.S. states of Minnesota, Michigan, Ohio, Pennsylvania, and New York.

Quebec

The Quebec border begins where the Ontario-New York border end in the St. Lawrence River at the 45th parallel north. The border heads inland towards the east, remaining on or near the parallel. At 45°00′N 71°30′W / 45.000°N 71.500°W / 45.000; -71.500, the border begins to follow various natural features of the Appalachian Mountains, continuing to do so until 46°25′N 70°03′W / 46.417°N 70.050°W / 46.417; -70.050, where it begins to head northbound, then northeastward at 46°41′N 69°59′W / 46.683°N 69.983°W / 46.683; -69.983. Finally, at 47°27′N 69°13′E / 47.450°N 69.217°E / 47.450; 69.217, the border heads toward Beau Lake, going through it and continuing into New Brunswick. From west to east, this border is shared with the U.S. states of New York, Vermont, New Hampshire, and Maine.

New Brunswick

The New Brunswick border begins at the southern tip of Beau Lake at 47°18′N 69°03′W / 47.300°N 69.050°W / 47.300; -69.050 and proceeds to the Saint John River. The border moves through the River until 47°04′N 67°47′W / 47.067°N 67.783°W / 47.067; -67.783, where it splits from the river and heads southward into the Chiputneticook Lakes at 45°56′N 67°47′W / 45.933°N 67.783°W / 45.933; -67.783, which subsequently leads the border to the St. Croix River. The border proceeds through the St. Croix to Passamaquoddy Bay, which then leads it to Grand Manan Island into the middle of the Bay of Fundy. Here, the border turns towards the south and terminates upon reaching international waters. This border is shared entirely with the U.S. state of Maine.