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

CountyDate FormedParent CountyCounty Seat
Bernalillo1852One of the nine original counties.Albuquerque
Catron1921Part of Socorro County.Reserve
Chaves1889Part of Lincoln County.Roswell
Cibola1981Part of Valencia County.Grants
Colfax1869Part of Mora County.Raton
Curry1909Parts of Quay and Roosevelt Counties.Clovis
De Baca1917Parts of Chaves and Guadalupe Counties.Fort Sumner
Dona Ana1852One of the nine original counties.Las Cruces
Eddy1889Part of Lincoln County.Carlsbad
Grant1868Part of Doña Ana County.Silver City
Guadalupe1891Part of San Miguel County.Santa Rosa
Harding1921Parts of Mora and Union Counties.Mosquero
Hidalgo1919Part of Grant County.Lordsburg
Lea1917Parts of Chaves and Eddy Counties.Lovington
Lincoln1869Part of Socorro County.Carrizozo
Los Alamos1949Parts of Sandoval and Santa Fe Counties.Los Alamos
Luna1901Parts of Doña Ana and Grant Counties.Deming
McKinley1899Part of Bernalillo County.Gallup
Mora1860Part of Taos County.Mora
Otero1899Parts of Doña Ana and Lincoln Counties.Alamogordo
Quay1903Part of Guadalupe County.Tucumcari
Rio Arriba1852One of the nine original counties.Tierra Amarilla
Roosevelt1903Parts of Chaves and Guadalupe Counties.Portales
San Juan1887Part of Bernalillo County.Bernalillo
San Miguel1852Part of Rio Arriba County.Aztec
Sandoval1903One of the nine original counties.Las Vegas
Santa Fe1852One of the nine original counties.Santa Fe
Sierra1884Parts of Doña Ana and Socorro Counties.Truth or Consequences
Socorro1852One of the nine original counties.Socorro
Taos1852One of the nine original counties.Taos
Torrance1903Parts of Bernalillo and Valencia Counties.Estancia
Union1893Parts of Colfax, Mora and San Miguel Counties.Clayton
Valencia1852One 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.