Fort Atkinson ( Nebraska ) " ( See also , Fort Atkinson , Wisconsin ) " Fort Atkinson was the first United States Army post to be established west of the Missouri River in the unorganized region of the Louisiana Purchase of the United States . Located just east of present - day Fort Calhoun , Nebraska , the fort was erected in 1819 and abandoned in 1827 . The site is now known as Fort Atkinson State Historical Park and is a National Historic Landmark . A replica fort was constructed by the state at the site during the 1980s - 1990s . The post , which included soldiers , traders , trappers , and other frontier people , has been credited by the Nebraska State Legislature as the first town in Nebraska . Founded almost 30 years before the creation of the Nebraska Territory , Fort Atkinson had more than 1 , 000 residents . It included a brickyard , lime kiln , stone quarry , grist mill , saw mill , and cooper shop . Lewis and Clark . The site that would become Fort Atkinson was the Council Bluff ( not to be confused with Council Bluffs , Iowa , 20 miles to the south ) used for an 1804 council between the Lewis and Clark Expedition and members of the Oto and Missouria Native American tribes . William Clark recommended the high bluff overlooking the Missouri River to the United States government as a suitable location to build a fort . Council Bluff : frontier post . Fifteen years later , in 1819 , President James Monroe dispatched a military expedition ( the Yellowstone Expedition , led by Colonel Henry Atkinson ) to establish a series of forts along the Missouri . These forts were to support the American fur trade and counteract British influence on the northern plains . The 6th US Infantry and 1st Rifle Regiments made up the military portion of the expedition , which arrived at the Council Bluff site on September 19 . It was located near Fort Lisa and Cabanne ' s Trading Post , private fur trading establishments operated by major traders who were based in St . Louis , Missouri . The expedition stopped to build Cantonment Missouri , a winter camp along the river bottom below the bluffs . Abandoning plans to establish more forts upstream , the soldiers settled in for winter . The winter of 1819 - 20 was very harsh ; a shortfall of government contractors left the garrison without sufficient supplies . The soldiers suffered widespread scurvy ( due to poor nutrition and lack of vitamin C ) , which claimed the lives of over 200 of the 1 , 120 men that first winter . Estimates of the civilian deaths is possibly as high as double the military dead ; no records were kept of their losses . In the spring of 1820 , the Missouri River flooded Cantonment Missouri . The soldiers built a permanent camp atop Council Bluff , and renamed it Fort Atkinson . Originally , the fort was to be named " Fort Calhoun " in honor of the Secretary of War , John C . Calhoun , but its first commander was honored . During the 1820s , soldiers took meteorological observations as research for the government . The garrison was involved in combat only in 1823 . Members of the Arikara tribe attacked a trading post along the Missouri River in present - day South Dakota . Soldiers from the fort retaliated by attacking an Arikara village . Although no American soldiers died in the brief skirmish , seven soldiers drowned on the way upriver when their keelboat struck a log . They were counted as the first United States ' casualties in the Indian Wars on the Great Plains . In 1827 , the Army abandoned the fort at Council Bluff and reassigned its personnel to other locations . Re - activation of Fort Atkinson . When the Mormons established Cutler ' s Park in the North Omaha area in 1846 , some of their food for the harsh winter was provided from old provisions they found at the fort . By the 1850s , when widespread European - American settlement began in the area , little remained of the fort . In the 1950s , Nebraska State Historical Society archeological crews determined the locations of buildings at the Fort Atkinson site . The Nebraska Game and Parks Commission gained title to the site in 1971 . During the 1980s and 1990s , it reconstructed the fort . Today , Fort Atkinson is a Nebraska state historical park , which includes a military museum . It was designated a National Historic Landmark . Living history demonstrations take place on the first weekend of each month from May to October . In addition to people demonstrating craft work and the duties of the Indian agent , military re - enactors interpret the activities of the Sixth Regiment of United States Infantry and First Regiment of United States Riflemen .