In 1803, when the prairie of the Northwest was home to the various tribes of the Native Americans, Thomas Jefferson bought the land to the west of the Mississippi River from the French. The deal known as the Louisiana Purchase was made to expand the country and allow more room for the growing population. The country had the need for forts in the wilderness to at first protect the Indians from the settlers and later to protect the settlers from the Indians, as the settlers moved west. In September 1805, Lt. Zebulon Pike was sent to scout the land of the upper Mississippi for a suitable place to build a fort. He camped at what is now “Pikes Island” at the mouth of the St. Peter’s river (later called the Minnesota). The land was bought for $200.00 worth of trinkets, an agreement to build a trading post, and a trader’s keg of whiskey. Later, an additional amount of $2,000.00 was given to the Dakota. As Pike put it in a letter to, Gen. James Wilkerson, “One hundred thousand acres for a song”. In 1816, the federal government, started the program of building the forts, of Fort Howard at Green Bay, Fort Armstrong at Rock Island and Fort Crawford at Prairie Du Chien. In 1817, Secretary of War John C. Calhoun, inaugurated his plan to build a fort at the head of the Mississippi from the survey of Major Steven Long. The original survey said to build it at St. Anthony falls, further up the river. But Long decided it was better to be built on the bluffs, at the convergence of the two rivers, as it commanded both from this point.
(Information from the book "Ft. Snelling/Colossus of the Wilderness" by the Minnesota Historical Society and rewritten by webmaster)