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 which predate the present U.S. Constitution. The Admission to the Union Clause also forbids the creation of new states from parts of existing states without the consent of both the affected states and Congress. The primary intent of this caveat was to give Eastern states that still had western land claims (there were four at that time) a veto over whether their western counties could become states. This clause has served the same function since, each time a proposal to partition an existing state or states has arisen. Article IV, Section 3, Clause 1: Between 1781 and 1789 the United