Confederate Arizona was a territory claimed by the Confederate States of America during the American Civil War, between 1861 and 1865. It consisted of the portion of the New Mexico Territory south of the 34th parallel north including parts of the modern states of New Mexico and Arizona. Its capital was Mesilla along the southern border. The Confederate territory overlapped the Arizona Territory created by the Union government in 1863, but the physical geography differed in that the Confederate Arizona Territory was approximately the southern half of the pre-existing New Mexico Territory, while the Union Arizona Territory was approximately the western half of what had been New Mexico Territory.
The territory was officially declared on August 1, 1861, following the Confederate victory at the Battle of Mesilla. Confederate hold in the area was soon broken, however, after the Battle of Glorieta Pass, the defining battle of the New Mexico Campaign. In July 1862, the government of the Confederate Territory of Arizona relocated to El Paso, Texas, where it remained for the duration of the war. The territory continued to be represented in the Confederate Congress and Confederate troops continued to fight under the Arizona banner until the war's end.