Santa Ana County, New Mexico Genealogy
- Up until 1821 - New Spain controlled land that later would become New Mexico and Arizona. Some records of early settlers may have been sent to an archives in Seville, Spain, or to archives in Mexico City.
- From 1821 until 1846 - Mexico had jurisdiction over the land that later would become New Mexico and Arizona. Some records of this period may have been sent to archives in Mexico City.
- 22 September 1846 - Santa Ana County was created based on an old Mexican government partido as one of seven original New Mexico counties under General Stephen W. Kearny's Kearny Code of laws for the occupied Mexican territory. It formally became a part of the United States when the Mexican-American War ended in 1848 with the signing of the Treaty of Guadalupe Hidalgo.
- 9 January 1852 - All New Mexico counties were redefined. Santa Ana county was extended west to the California border including land in present day Arizona and Nevada.  
There is a small chance that a few records from 1846 to 1863 in what is now Arizona may have been sent to courthouses in their respective New Mexico counties.
- 29 December 1863 Arizona's three judicial districts were established by the Arizona Territory Organic Act from the western half of New Mexico Territory.
All previous counties were dissolved, and eventually four new counties were created in the new Arizona Territory.
- 1876 The remaining portion of Santa Ana County survived in New Mexico until it was extinguished by being absorbed into Bernalillo County, New Mexico.
For Santa Ana County records, see Bernalillo County, New Mexico.
The first county seat was Fort Defiance just west of the current Arizona-New Mexico border. For 1847 to 1863 it was part of Judicial District 1, and thereafter Judicial District 2.
- "Courts and Judicial Powers, Sec. 6” Kearny Code: Laws for the Government of the Territory of New Mexico, September 22, 1846 (Santa Fe, N. Mex.: S. W. Kearny, 1846), 47. Digital online edition.
- N.M. Terr. Laws 1851, 1st assy., 2d sess. /p. 291
- William Thorndale, and William Dollarhide, Map Guide to the U.S. Federal Censuses, 1790-1920 (Baltimore: Genealogical Publishing, 1987), 26. At various libraries (WorldCat); FHL Book 973 X2th.
- Original Counties of New Mexico Territory (map) at http://www.nmgs.org/Graphics/nmcoun-orig.jpg (accessed 9 August 2011).
- Wikipedia contributors, "1st Arizona Territorial Legislature" in Wikipedia: the Free Encyclopedia at http://en.wikipedia.org/wiki/1st_Arizona_Territorial_Legislature (accessed 8 August 2011).
- Wikipedia contributors, "Santa Ana County, New Mexico Territory" in Wikipedia: the Free Encyclopedia at http://en.wikipedia.org/wiki/Santa_Ana_County,_New_Mexico_Territory (accessed 11 September 2012).