Arizona is a state located in the southwestern region of the United States of America. The capital and largest city is Phoenix. The three next largest cities are Tucson, Mesa and Glendale. Arizona was the 48th and last of the contiguous states admitted to the Union on February 14, 1912. Arizona is noted for its desert climate, exceptionally hot summers and mild winters, but the high country in the north features pine forests and mountain ranges which contrast with the lower deserts. New population figures for the year ending July 1, 2006, indicate that Arizona is the fastest growing state in the United States, exceeding the growth of the previous leader, Nevada.

Arizona is one of the Four Corners states. It borders New Mexico, Utah, Nevada, California, touches Colorado, and has a 389 mi (626 km) international border with the states of Sonora and Baja California in Mexico. Aside from the Grand Canyon, many other National Forests, Parks, Monuments, and Indian reservations are located in the state.