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.