Arizona County Creation Dates and Parent Counties

United States Arizona  County Creation Dates

Arizona Territory was created on 24 February 1863 from the west half of New Mexico Territory. All previous counties were discontinued, but new counties were not created until 10 November 1864, when the first four counties were created. The last county created was La Paz on 27 April 1983. In the present day there are a total of 15 counties; 8 of them named for Native American Tribes, 2 of them for People, 2 of them for Mountains, 2 of them for Rivers, and 1 of them for a Town.

Arizona Atlas of Historical County Boundaries Detailed information of historical county boundary changes.