Saint John River (Bay of Fundy)

The St. John River is a river, approximately 418 mi (673 km) long, in the U.S. state of Maine and the Canadian province of New Brunswick, forming part of the U.S.-Canada border in two places along its length.

It rises in Somerset County in northwestern Maine and flows NE, forming approximately 15 miles of the border between Maine and Quebec, then into northern Maine, through western Aroostook County. Near Allagash, it is joined by the Allagash River. Below St. Francis, it forms part of the border between Maine and New Brunswick. Flowing northeast, it passes Fort Kent, Maine, and between Edmundston, New Brunswick and Madawaska, Maine, where it turns southeast, flowing between Van Buren, Maine and St. Leonard, New Brunswick. Near Grand Falls, New Brunswick it enters New Brunswick, flowing south, through the fertile St. John Valley, roughly parallel to the international border, where it is joined by the Aroostook and the Tobique rivers. At the mouth of the valley near Woodstock, it turns southeast, flowing past Fredericton, where it becomes navigable, and Oromocto, then south in a widening fjord estuary cut by several lateral bays, including Belleisle Bay and Kennebecasis Bay. It enteres the Bay of Fundy at Grand Bay near St. John. At the Reversing Falls Rapids at its mouth in St. John, the river changes direction diurnally due to the strong tides of the Bay of Fundy.

In 1604, the river was explored by Samuel de Champlain and Sieur de Monts. It was an important trade route for French, English and First Nations traders during the 17th and 18th century. The river is used for hydroelectric power at Grand Falls (where the river descends in a steep cataract), and at Beechwood and Mactaquac. The St. John Valley is a primary area for the cultivation of potatoes.