Created by the Kansas-Nebraska Act on May 30, 1854, the Nebraska Territory spanned all of the current day state of Nebraska, most of Wyoming and Montana, and part of Colorado and the Dakotas. Congress ceded the portion of Colorado to the Colorado Territory in 1861 and all of the territory in the Dakotas and Montana to the Dakota Territory that same year. Part of Wyoming was also ceded to the Dakota Territory but the southern half of the state remained part of the Nebraska Territory until 1863, when it was absorbed by the newly-created Idaho Territory. Omaha was chosen as capital by the first territorial assembly on February 22, 1855, and remained so for the duration of the territory’s existence despite several legislative attempts to remove the capital to a different location.
“An Act to Organize the Territories of Nebraska and Kansas,” 30 May 1854, Statutes at Large of the United States 10 (1855):277-90; “An Act to Provide a Temporary Government for the Territory of Colorado,” 28 February 1861, Statutes at Large of the United States 12 (1863):172-77; “An Act to Provide a Temporary Government for the Territory of Dakota, and to Create the Office of Surveyor General Therein,” 2 March 1861, Statutes at Large of the United States 12 (1863):239-44; “An Act to Provide a Temporary Government for the Territory of Idaho,” 3 March 1863, Statutes at Large of the United States 12 (1863):808-14; James B. Potts, “The Nebraska Capital Controversy, 1854-59,” Great Plains Quarterly 8 (Summer 1988): 173, 180.