Vincennes, IN played a critical role in the fact that the American interior belongs to the United States and is not part of Canada. French traders from Quebec first settled this town along the Wabash River about 1702. After England captured Quebec from France in 1760, the British took over Fort Vincennes and renamed it Fort Sackville in 1766. From here & other locations, like Detroit, the British prevented Americans from settling on Indian lands, a major cause of the American Revolution. When the Revolution came in 1776, these British forts, threatened the American colonies because the British could use them to invade American southern states from the west.
Thus the Americans sent George Rogers Clark and a couple hundred men to neutralize British forces which they did at first by winning the French as allies. But the British soon reinforced Fort Sackville. Rogers and 170 volunteers undertook to catch the Fort off guard and in Feb. 1779, they waded for days through icy, shoulder-deep wetlands and rivers. Under barrage, the fort surrendered on Feb. 25, 1779, making the area from the Appalachians to the Mississippi River part of the United States.
After the Revolution, the United States, these Northwest Territories or Indiana Territories, were governed from Vincennes under Territorial Governor William Henry Harrison, who built an impressive mansion called Grouseland and set about to tame various Indian uprisings. Over time Indiana was split into the states of Ohio, Indiana, Illinois, Michigan, Wisconsin & a portion of Minnesota.