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 New Mexico counties were discontinued, but it was not until 10 November 1864, when the first four Arizona counties were created. Pah-Ute county is the only county discontinued, in 1871. All the other created counties still continue. 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.
- An animated map of Arizona county changes is found at Pima County History (scroll down)
- Arizona Atlas of Historical County Boundaries contains detailed information of historical county boundary changes.
- Previous Jurisdictions to Land in Arizona showing dates the jurisdictions were created and maps. This will help in determining what jurisdiction your ancestor lived in and where the records are now located.
The information listed below is useful in identifying which county your ancestor lived in at what time. Once you have that information, you can contact that county's offices for records of your ancestor. If you don't find records in the identified county, look in nearby counties. Some changes have been made to the boundaries of the counties since they were created.
 |
Sort the table by Date Formed or by Parent Counties and check Boundary Changes for interesting insights. |
| Name of County | Date Formed | Parent County | Boundary Changes | Counties Created by Boundary Changes |
| Apache | 1879 Feb 14 | Yavapai | Details | Graham 1881, Navajo 1895 |
| Cochise | 1881 Feb 1 | Pima | Details | none |
| Coconino | 1891 Feb 19 | Yavapai | Details | none |
| Gila | 1881 Feb 8 | Maricopa, Pinal | Details | none |
| Graham | 1881 Mar 10 | Apache, Pima | Details | Greenlee 1909 |
| Greenlee | 1909 Mar 10 | Graham | Details | none |
| La Paz | 1983 Apr 27 | Yuma | Details | none |
| Maricopa | 1871 Feb 14 | Yavapai | Details | Pinal 1875, Gila 1881 |
| Mohave | 1864 Nov 10 | Arizona territory | Details | Pah-Ute 1865, portion to Nevada 1866 |
| Navajo | 1895 Mar 21 | Apache | Details | none |
| Pah-Ute | 1865 Dec 22 | Mohave | Details | portion to Nevada 1866, disbanded 1871 |
| Pima | 1864 Nov 10 | Arizona territory | Details | Pinal 1875, Cochise 1881, Graham 1881, Santa Cruz 1899 |
| Pinal | 1875 Feb 1 | Pima, Maricopa | Details | none |
| Santa Cruz | 1899 Mar 15 | Pima | Details | none |
| Yavapai | 1864 Nov 10 | Arizona territory | Details | Maricopa 1871, Apache 1879, Coconino 1891 |
| Yuma | 1864 Nov 10 | Arizona territory | Details | La Paz 1983 |
 |
See an interactive outline map of Arizona Historical Counties at Newberry Library site. [1] (Free) Enter a year, Refresh Map, select zoom in, then click on the map to enlarge it. |
- ↑ [https://publications.newberry.org/ahcbp/map/map.html#AZ Arizona Atlas of Historical County Boundaries, John H. Long, Editor; Peggy Tuck Sinko, Associate Editor; Gordon DenBoer, Historical Compiler; Douglas Knox, Book Digitizing Director and Digital Compiler; Emily Kelley, Research Associate; Laura Rico-Beck, GIS Specialist; Peter Siczewicz, ArcIMS Interactive Map Designer; Robert Will, Cartographic Assistant. Copyright The Newberry Library 2008.
