Arizona states of Sonora and Baja California. Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912, coinciding with Valentine's Day. Historically part of the territory of "Alta California" in New Spain, it became part of independent Mexico in 1821. After being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848. The southernmost portion of the state was acquired in 1853 through the Gadsden Purchase. Southern Arizona is known for its desert climate, with very hot summers and mild winters.
Admission to the Union formed in the Northwest Territory under either ordinance. In August, 1789, the ordinance was replaced by the Northwest Ordinance of 1789, in which the new Congress (under the present Constitution) reaffirmed the Ordinance with slight modifications. The territory itself remained in existence until 1803, when the southeastern portion of it was admitted to the Union as the State of Ohio, and the remainder was reorganized. While the articles of Confederation were in effect, the Congress considered various ordinances admitting particular new states into the Union, none of which were approved: At the 1787 Constitutional Convention, a proposal to include the