Just on the east side of Fort Calhoun is Fort Atkinson State Historical Park. Fort Atkinson has the distinction of being the first United States Army post established west of the Missouri river. The fort was established in 1819, then later abandoned in 1827. Up to 1200 U.S. Army soldiers were garrisoned at Fort Atkinson. The fort also served as a trading post, which also hosted traders, trappers, and other frontier people. Many famous western explorers passed through Fort Atkinson. Fort Atkinson has also been credited by the Nebraska State Legislature as the first town in the state, founded almost thirty years prior to the creation of the Nebraska Territory.