Which countries share the longest border?
Canada and the United States share the longest international border in the world, about 8,891 kilometers long, including the border between Alaska and Canada.
The border runs across North America from the Atlantic to the Pacific along the 49th parallel for much of its length, then through the Great Lakes and the St. Lawrence River. Separately, about 2,475 kilometers of border divide Alaska from Canada's Yukon and British Columbia. Thirteen US states border Canada.
An organization called the International Boundary Commission maintains the border, keeping a cleared strip of land about six meters wide through forests, called the slash, so the line is visible. There are about 120 land ports of entry between the two countries.
Other long borders
The second-longest border is between Kazakhstan and Russia, at about 7,600 kilometers. Argentina and Chile share a long border along the Andes, about 5,300 kilometers. China borders 14 countries, tied with Russia for the most neighbors of any country.
Did You Know?
The Haskell Free Library and Opera House sits right on the border between Vermont and Quebec. A black line on the floor marks the boundary.