County Offices of many states are a great place to start your research.  We have provided a brief glimpse of the etymology of each county, knowing when and how counties were formed can aid land and census searches. Many counties were named for families living in the area, government officials even if they never lived in that county or state.  Visiting the county site you should be able to obtain additional information for your research. 


Bernalillo County >> Bernalillo County Website

County Seat: Albuquerque
Created: 1852
Formed From: One of the nine original counties.
Etymology: Named for either the nearby settlement of Bernalillo, New Mexico of the Gonzales-Bernal family which lived in the future county in the seventeenth century.

Catron County >> Catron County Website

County Seat: Reserve
Created: 1921
Formed From: Part of Socorro County
Etymology: Thomas Benton Catron, a Santa Fe attorney and New Mexico’s first US Senator

Chaves County >> Chaves County Website

County Seat: Roswell
Created: 1889
Formed From: Part of Lincoln County
Etymology: Jose Francisco Chaves, a US Army colonel in New Mexico during and after the Civil War.

Cibola County >> Cibola County Website

County Seat: Grants
Created: 1891
Formed From: Part of Valencia County
Etymology: Seven Cities of Cibola

Colfax County >> Colfax County Website

County Seat: Raton
Created: 1869
Formed From: Part of Mora County
Etymology: Schuyler Colfax, the seventeenth vice president of the United States.

Curry County >> Curry County Website

County Seat: Clovis
Created: 1909
Formed From: Parts of Quay County and Rosevelt County
Etymology: George Curry, a governor of New Mexico Territory from 1907 to 1910.

De Baca County >> None Listed

County Seat: Fort Sumner
Created: 1917
Formed From: Parts of Chaves County and Guadalupe County
Etymology: Ezequiel Cabaza de Baca, the second state governor of New Mexico

Doña Ana County >> Doña Ana County Website

County Seat: Las Cruces
Created: 1852
Formed From: One of the nine original counties.
Etymology: Named for its first county seat of Doña Ana, New Mexico, which in turn was named for Doña Ana Robledo, a 17th century woman known for her charitable giving.

Eddy County >> Eddy County Website

County Seat: Carlsbad
Created: 1887
Formed From: Part of Lincoln County
Etymology: Charles Eddy, a rancher and developer of the area.

Grant County >> Grant County Website

County Seat: Silver City
Created: 1868
Formed From: Part of Doña Ana County
Etymology: Ulysses Simpson Grant, the Civil War general and eighteenth president of the United States.

Guadalupe County >> None Listed

County Seat: Santa Rosa
Created: 1891
Formed From: Part of San Miguel County
Etymology: Our Lady of Guadalupe, the patron saint of the Americas

Harding County >> Harding County Website

County Seat: Mosquero
Created: 1921
Formed From: Parts of Mora County and Union County.
Etymology: Warren Gamaliel Harding, the twenty-ninth president of the United States.

Hidalgo County >> Hidalgo County Website

County Seat: Lordsburg
Created: 1920
Formed From: Part of Grant County
Etymology: Miguel Hidalgo y Costilla, the priest who is known as the Father of Mexican Independence.

Lea County >> Lea County Website

County Seat: Lovington
Created: 1917
Formed From: Parts of Chaves County and Eddy County.
Etymology: Joseph Calloway Lea, a captain in the US Army, prominent leader in Chaves County and founder of the New Mexico Military Academy.

Lincoln County >> Lincoln County Website

County Seat: Carrizozo
Created: 1869
Formed From: Part of Socorro County
Etymology: Abraham Lincoln, the sixteenth president of the United States.

Los Alamos County >> Los Alamos County Website

County Seat: Los Alamos
Created: 1949
Formed From: Parts of Sandoval County and Santa Fe County.
Etymology: Named for its county seat of Los Alamos, New Mexico.

Luna County >> Luna County Website

County Seat: Deming
Created: 1901
Formed From: Parts of Doña Ana County and Grant County.
Etymology: Named for its county seat of Los Alamos, New Mexico.

McKinley County >> McKinley County Website

County Seat: Gallup
Created: 1899
Formed From: Parts of Bernalillo County.
Etymology: William McKinley, the twenty-fifth president of the United States.

Mora County >> Mora County Website

County Seat: Mora
Created: 1859
Formed From: Part of Taos County.
Etymology: Named for its county seat of Mora, New Mexico.

Otero County >> Otero County Website

County Seat: Alamogordo
Created: 1899
Formed From: Parts of Doña Ana County and Lincoln County.
Etymology: Miguel A. Otero, territorial delegate to the US Congress.

Quay County >> Quay County Website

County Seat: Tucumcari
Created: 1903
Formed From: Part of Guadalupe County.
Etymology: Matthew Stanley Quay, a US Senator from Pennsylvania who supported New Mexico’s statehood.

Rio Arriba County >> Rio Arriba County Website

County Seat: Tierra Amarilla
Created: 1852
Formed From: One of the nine original counties.
Etymology: Named for its location on the upper Rio Grande (Rio Arriba is “upper river” in Spanish.

Roosevelt County >> Rosevelt County Website

County Seat: Portales
Created: 1903
Formed From: Parts of Chaves County and Guadalupe County.
Etymology: Theodore Roosevelt, the twenty-sixth president of the United States.

Sandoval County >> Sandoval County Website

County Seat: Bernalillo
Created: 1903
Formed From: Part of Bernalillo County.
Etymology: Named for the Sandoval family which lived in the area.

San Juan County >> San Juan County Website

County Seat: Aztec
Created: 1887
Formed From: Part of Rio Arriba County.
Etymology: San Juan River.

San Miguel County >> San Miguel County Website

County Seat: Las Vegas
Created: 1852
Formed From: One of the nine original counties.
Etymology: San Miguel de Bado, New Mexico.

Santa Fe County >> Santa Fe County Website

County Seat: Santa Fe
Created: 1852
Formed From: One of the nine original counties.
Etymology: Santa Fe, New Mexico, which is also the state capital.

Sierra County >> Sierra County Website

County Seat: Truth or Consequences
Created: 1884
Formed From: Parts of Doña Ana County and Socorro County
Etymology: Possibly named for the Black Range. (Sierra is mountain range in Spanish)

Socorro County >> None listed

County Seat: Socorro
Created: 1852
Formed From: One of the nine original counties.
Etymology: Named for its county seat of Socorro, New Mexico

Taos County >> Taos County Website

County Seat: Taos
Created: 1852
Formed From: One of the nine original counties.
Etymology: Named for its county seat of Taos, New Mexico, which was named for Taos Pueblo, an ancient Native American village.

Torrance County >> Torrance County Website

County Seat: Estancia
Created: 1903
Formed From: Parts of Bernalillo County and Valencia County.
Etymology: Francis J. Torrance, a developer of the New Mexico Central Railroad.

Union County >> None listed

County Seat: Clayton
Created: 1893
Formed From: Parts of Colfax County, Mora County and San Miguel County.
Etymology: Named for the union of three counties which donated land to form the new county.

Valencia County >> Valencia County Website

County Seat: Los Lunas
Created: 1852
Formed From: One of the nine original counties.
Etymology: Named for the town of Valencia, New Mexico in the county.