Arizona is a state in the Western United States, grouped in the Southwestern and occasionally Mountain subregions. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona shares the Four Corners region with Utah to the north, Colorado to the northeast, and New Mexico to the east; its other neighboring states are Nevada and California to the west and the Mexican states of Sonora and Baja California to the south and southwest.