Arizona is organized as a United States territory

Background. Prior to 1863, Congress resisted Arizona statehood due to fears it would become a slave state. Business interests from Ohio sought territorial status for silver mining. The New Mexico Territory had a history of enslaving Native Americans. The Gadsden Purchase in 1853 expanded the territory, leading to proposals for a separate Arizona territory, including a 1858 resolution favoring a north-south border.

Legislative Process. The Arizona Organic Act was introduced as H.R. 357 in the second session of the 37th U.S. Congress. The House, devoid of southern delegates, passed a bill using a north-south border along the 109th meridian. This choice denied de facto ratification of the Confederate Arizona Territory. The final bill passed the Senate in February 1863 without the Tucson-as-capital stipulation.

Organization and Capital. President Abraham Lincoln signed the bill on February 24, 1863, officially organizing the U.S. Arizona Territory. The first capital was established in 1864 at Prescott in the northern Union-controlled area. The capital was later moved to Phoenix on February 4, 1889. Governor Goodwin announced the organization by virtue of powers invested by an act of Congress providing a temporary government.