Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912. 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.
The state has a wide range of elevations, from sea level on the coast to 6,684 feet (2,037 m) at Mount Mitchell, the highest point in North America east of the Mississippi River. The climate of the coastal plains is strongly influenced by the Atlantic Ocean. Most of the state falls in the humid subtropical climate zone. More than 300 miles (500 km) from the coast, the western, mountainous part of the state has a subtropical highland climate.