Arizona became the 48th and last of the contiguous United States in 1912. President William Howard Taft signed the statehood proclamation on February 14, 1912.
New Mexico entered the Union as the 47th state on January 6, 1912, followed by Arizona less than six weeks later. Arizona’s admission completed the contiguous United States as it existed before Alaska and Hawaii joined in 1959.
Arizona had previously been part of the Arizona Territory, which was separated from New Mexico Territory in 1863. Its statehood process included debates about its proposed constitution and political structure. Arizona is often remembered for the Grand Canyon, which became a national park in 1919, seven years after statehood.