February 24, 1863 Arizona becomes a territory Most of what is
now Arizona came into the possession of the US in 1848 after the
Mexican-American War. In 1850, it became part of the Territory
of New Mexico, which also included the southern parts of
Colorado, Nevada, and Utah. More land was added in 1854 when the
Gadsden Treaty was signed. In 1858, there was a request for the
creation of an Arizona teritory. The Civil War did nothing to
help the process as both sides wanted Arizona. Finally, however,
Congress approved the creation of the Territory of Arizona and
President Abraham Lincoln signed the bill on February 24, 1863.