New Mexico Counties and Historical Facts

New Mexico County records vary widely from county to county in both quality and quantity. Some have been carefully preserved while others have been much abused and neglected. Some New Mexico records have simply disappeared. For genealogists doing research in New Mexico there is no effective replace for an on-site search of county courthouse records. For Definitions of all court terms see the Genealogy Encyclopedia.

New Mexico is divided into 33 counties. There were originally nine counties formed in 1852. Santa Ana County, New Mexico Territory, one of the nine original counties, was annexed in 1876 to Bernalillo County, New Mexico.

The county seat’s county clerk’s office retains some probate records, as well as plats, surveys, mining records, deeds, land records, and records pertaining to marriages. They also have files containing mortgages, liens, powers of attorney, military discharges and other documents and affidavits. The district clerk’s office holds records pertaining to probate matters.

The New Mexico State Records Center and Archives has records on file that predate formal county organizations and certain counties may also have similar records on file from Mexican and Territorial times. See also a list of links to county and county seat government run websites.

List of New Mexico Counties

County Date Formed Parent County County Seat
Bernalillo 1852 One of the nine original counties. Albuquerque
Catron 1921 Part of Socorro County. Reserve
Chaves 1889 Part of Lincoln County. Roswell
Cibola 1981 Part of Valencia County. Grants
Colfax 1869 Part of Mora County. Raton
Curry 1909 Parts of Quay and Roosevelt Counties. Clovis
De Baca 1917 Parts of Chaves and Guadalupe Counties. Fort Sumner
Dona Ana 1852 One of the nine original counties. Las Cruces
Eddy 1889 Part of Lincoln County. Carlsbad
Grant 1868 Part of Doña Ana County. Silver City
Guadalupe 1891 Part of San Miguel County. Santa Rosa
Harding 1921 Parts of Mora and Union Counties. Mosquero
Hidalgo 1919 Part of Grant County. Lordsburg
Lea 1917 Parts of Chaves and Eddy Counties. Lovington
Lincoln 1869 Part of Socorro County. Carrizozo
Los Alamos 1949 Parts of Sandoval and Santa Fe Counties. Los Alamos
Luna 1901 Parts of Doña Ana and Grant Counties. Deming
McKinley 1899 Part of Bernalillo County. Gallup
Mora 1860 Part of Taos County. Mora
Otero 1899 Parts of Doña Ana and Lincoln Counties. Alamogordo
Quay 1903 Part of Guadalupe County. Tucumcari
Rio Arriba 1852 One of the nine original counties. Tierra Amarilla
Roosevelt 1903 Parts of Chaves and Guadalupe Counties. Portales
San Juan 1887 Part of Bernalillo County. Bernalillo
San Miguel 1852 Part of Rio Arriba County. Aztec
Sandoval 1903 One of the nine original counties. Las Vegas
Santa Fe 1852 One of the nine original counties. Santa Fe
Sierra 1884 Parts of Doña Ana and Socorro Counties. Truth or Consequences
Socorro 1852 One of the nine original counties. Socorro
Taos 1852 One of the nine original counties. Taos
Torrance 1903 Parts of Bernalillo and Valencia Counties. Estancia
Union 1893 Parts of Colfax, Mora and San Miguel Counties. Clayton
Valencia 1852 One of the nine original counties. Los Lunas

List of New Mexico Extinct Counties

New Mexico has counties that no longer exist. They were established by the state, provincial, or territorial government. Most of these counties were created and disbanded in the 19th century; county boundaries have changed little since 1900 in the vast majority of states. These counties need to be looked at when doing genealogy research. Pay close attention where the courthouse records went to if the county was abolished or combined with another county.

  • Santa Ana County [1852 Map]was one of the seven original partidos created in New Mexico under Mexican rule (was in Judicial District No. 1 from 1847 to 1863, then in JD 2 until 1876). Under U.S. rule, it became a U.S. Territorial county from 1852 until 1876, when it was absorbed by Bernalillo County.

List of New Mexico Counties with Burned Courthouses

The damage to courthouses greatly has a bearing on genealogists in every way. No only are these historic structures torn from our lifetimes, so are the records they housed: marriage, wills, probate, land records, and others. Once destroyed they’re lost forever. Although they have been placed on mircofilm, computers and film burn too. The most heartbreaking side of this is the reason that nearly all of our courthouses are destroyed at the hands of arsonist. Although, not all records were lost. Many New Mexico counties have suffered a loss of records due to
courthouse fires, floods, and theft.

  • Sandoval County Courthouse had a Record loss in 1926.