Previous Jurisdictions to Land in Arizona

Previous Jurisdictions and Record Repositories
Locating records of your ancestors
 * Find where your ancestor lived
 * Identify when your ancestor live there
 * Locate the jurisdiction covering the land where your ancestor lived
 * Determine the record repositories for that jurisdiction

For example, suppose you believe your ancestor lived in Tucson, Arizona in 1861. Putting this altogether, your ancestor actually lived in Tucson, Arizona County, New Mexico Territory in 1861. Therefore look for records in Tucson, Dona Ana County, and the State of New Mexico archives.
 * In the present day, Tucson is indeed located in the State of Arizona.
 * But Arizona didn't exist in 1856. Arizona Territory wasn't created until 1863.
 * Before that, the land belonged to New Mexico Territory, which was created in 1850. Your ancestor lived in New Mexico Territory. This jurisdiction still exists today as the State of New Mexico.
 * In 1853, the US bought the Gadsden Purchase from Mexico, which contained land south of the Gila River. This is the land where Tucson is located. In 1854, this land was given to New Mexico Territory and in 1855 this land was added to Dona Ana county.
 * Then in 1860, New Mexico created Arizona county from the land in Dona Ana county that existed in the present day State of Arizona. Your ancestor lived in Arizona County in the New Mexico Territory. But Arizona county was discontinued in 1862, then recreated in 1863 and finally discontinued again when Arizona Territory was created in 1863. The records from this extinct county are to be found in Dona Ana County, which exists today.

Sometimes, records were recorded in a county where your ancestor did not live. Maybe there was confusion as to where the borders were. Or maybe it was a shorter distance to the neighboring county seat. There could be several reasons, so don't overlook records in nearby counties. But treat this as the exception to the rule and check the most obvious county first.