There are 33 counties in the U.S. state of New Mexico. First there were nine counties formed in 1852.

The Federal Information Processing Standard (FIPS) code, used by the United States government to uniquely identify states and counties, is provided with each entry.^[1] New Mexico's code is 35. When added with any county code it would be written as 35XXX. The FIPS code for each county links to census data for that county.

County	FIPS Code [2]	County Seat [3]	Created [3]	Formed from [4]	Meaning of name [5]	Population (2020)[3]	Area [3]	Map
Bernalillo County	001	Albuquerque	1852	One of the nine original counties.	The Gonzales-Bernal family, Spanish nobles who settled the territory in the seventeenth century	676,444	1,166 sq mi (3,020 km2)
Catron County	003	Reserve	1921	Part of Socorro County.	Thomas Benton Catron (1840-1921), a Santa Fe attorney and New Mexico's first U.S. Senator	3,579	6,928 sq mi (17,943 km2)
Chaves County	005	Roswell	1889	Part of Lincoln County.	Jose Francisco Chaves (1833-1904), a U.S. Army colonel in New Mexico during and after the Civil War	65,157	6,071 sq mi (15,724 km2)
Cibola County	006	Grants	1981	Parts of Valencia County, Socorro County, McKinley County, and Catron County.	The mythical Seven Cities of Cibola	27,172	4,540 sq mi (11,759 km2)
Colfax County	007	Raton	1869	Part of Mora County.	Schuyler Colfax (1823-1885), the seventeenth vice president of the United States	12,387	3,757 sq mi (9,731 km2)
Curry County	009	Clovis	1909	Parts of Quay County and Roosevelt County.	George Curry (1861-1947), a governor of New Mexico Territory from 1907 to 1910	48,430	1,406 sq mi (3,642 km2)
De Baca County	011	Fort Sumner	1917	Parts of Chaves County and Guadalupe County.	Ezequiel Cabeza de Baca (1864-1917), the second state governor of New Mexico	1,698	2,325 sq mi (6,022 km2)
Doña Ana County	013	Las Cruces	1852	One of the nine original counties.	Doña Ana Robledo, a seventeenth-century Spanish woman known for her charitable giving to the native population	219,561	3,807 sq mi (9,860 km2)
Eddy County	015	Carlsbad	1887	Part of Lincoln County.	Charles Eddy (1857 - 1931), a rancher and developer of the area	62,314	4,182 sq mi (10,831 km2)
Grant County	017	Silver City	1868	Part of Doña Ana County.	Ulysses Simpson Grant (1822-1885), the Civil War general and eighteenth president of the United States	28,185	3,966 sq mi (10,272 km2)
Guadalupe County	019	Santa Rosa	1891	Part of San Miguel County.	Our Lady of Guadalupe, the patron saint of the Americas	4,452	3,031 sq mi (7,850 km2)
Harding County	021	Mosquero	1921	Parts of Mora County and Union County.	Warren Gamaliel Harding (1865-1923), the twenty-ninth president of the United States	657	2,126 sq mi (5,506 km2)
Hidalgo County	023	Lordsburg	1920	Part of Grant County.	The Treaty of Guadalupe Hidalgo, named after a Mexican town in turn named for Miguel Hidalgo y Costilla (1753 - 1811), the priest who is known as the Father of Mexican Independence	4,178	3,446 sq mi (8,925 km2)
Lea County	025	Lovington	1917	Parts of Chaves County and Eddy County.	Joseph Calloway Lea (1841-1904), a captain in the U.S. Army and the founder of the New Mexico Military Academy	74,455	4,393 sq mi (11,378 km2)
Lincoln County	027	Carrizozo	1869	Part of Socorro County.	Abraham Lincoln (1809-1865), the sixteenth president of the United States	20,269	4,831 sq mi (12,512 km2)
Los Alamos County	028	Los Alamos	1949	Parts of Sandoval County and Santa Fe County.	Named for its county seat of Los Alamos, New Mexico, which itself is the Spanish name for the cottonwood tree	19,419	109 sq mi (282 km2)
Luna County	029	Deming	1901	Parts of Doña Ana County and Grant County.	Solomon Luna (1858 - 1912), the largest land owner in the county at the time of its creation; itself Spanish for moon	25,427	2,965 sq mi (7,679 km2)
McKinley County	031	Gallup	1899	Part of Bernalillo County.	William McKinley (1843-1901), the twenty-fifth president of the United States	72,902	5,449 sq mi (14,113 km2)
Mora County	033	Mora	1859	Part of Taos County.	Named for its county seat of Mora, New Mexico, which is itself named after lo de mora, the Spanish term for blackberry	4,189	1,931 sq mi (5,001 km2)
Otero County	035	Alamogordo	1899	Parts of Doña Ana County and Lincoln County.	Miguel A. Otero (1829-1882), territorial delegate to U. S. Congress or Miguel Antonio Otero (II) (1859-1944), 16th Governor of New Mexico Territory from 1897 to 1906	67,839	6,627 sq mi (17,164 km2)
Quay County	037	Tucumcari	1903	Part of Guadalupe County.	Matthew Stanley Quay (1833-1904), a U.S. Senator from Pennsylvania who supported New Mexico's statehood	8,746	2,855 sq mi (7,394 km2)
Rio Arriba County	039	Tierra Amarilla	1852	One of the nine original counties.	Named for its location on the upper Rio Grande (Río Arriba means "upstream" or "up the river" in Spanish)	40,363	5,858 sq mi (15,172 km2)
Roosevelt County	041	Portales	1903	Parts of Chaves County and Guadalupe County.	Theodore Roosevelt (1858-1919), the twenty-sixth president of the United States	19,191	2,449 sq mi (6,343 km2)
Sandoval County	043	Bernalillo	1903	Part of Bernalillo County.	Named for the Sandoval family, prominent seventeenth-century Spanish landowners	148,834	3,710 sq mi (9,609 km2)
San Juan County	045	Aztec	1887	Part of Rio Arriba County.	San Juan River, itself named after the Catholic saint	121,661	5,514 sq mi (14,281 km2)
San Miguel County	047	Las Vegas	1852	One of the nine original counties.	San Miguel de Bado Catholic Church, the first in the area	27,201	4,717 sq mi (12,217 km2)
Santa Fe County	049	Santa Fe	1852	One of the nine original counties.	Named after the city of Santa Fe whose full Spanish name is “La Villa Real de la Santa Fe de San Francisco de Assisi” or “The royal city of the holy faith of St. Francis of Assisi”	154,823	1,909 sq mi (4,944 km2)
Sierra County	051	Truth or Consequences	1884	Parts of Doña Ana County and Socorro County.	Possibly named for the Black Range. (Sierra is mountain range in Spanish.)	11,576	4,180 sq mi (10,826 km2)
Socorro County	053	Socorro	1852	One of the nine original counties.	Spanish term meaning "aid," which refers to the help Native Americans gave to starving travelers	16,595	6,647 sq mi (17,216 km2)
Taos County	055	Taos	1852	One of the nine original counties.	Named for its county seat of Taos, New Mexico, which in turn was named for the nearby Taos Pueblo, an ancient Native American village. Taos is red willow in the Tiwa language	34,489	2,203 sq mi (5,706 km2)
Torrance County	057	Estancia	1903	Parts of Bernalillo County, Valencia County, and Socorro County.	Francis J. Torrance (1859 - 1919), the developer of the New Mexico Central Railroad	15,045	3,345 sq mi (8,664 km2)
Union County	059	Clayton	1893	Parts of Colfax County, Mora County and San Miguel County.	Named for the "union" of the three counties which donated land to form the new county	4,079	3,830 sq mi (9,920 km2)
Valencia County	061	Los Lunas	1852	One of the nine original counties.	Named for the town of Valencia, New Mexico, which is itself named for Valencia, Spain	76,205	1,068 sq mi (2,766 km2)

1. ↑ "FIPS Publish 6-4". National Institute of Standards and Technology. Archived from the original on 2013-09-29. Retrieved 2007-08-06.
2. ↑ "EPA County FIPS Code Listing". US Environmental Protection Agency. Retrieved 2007-08-06.
3. ↑ ^{3.0 3.1 3.2 3.3} National Association of Counties. "NACo County Explorer". Retrieved 17 January 2024.
4. ↑ "NMGenWeb Counties". Rootsweb.com. Archived from the original on 2007-07-02. Retrieved 2007-08-06.
5. ↑ "Viva New Mexico County Names". Archived from the original on 2008-07-04. Retrieved 2012-03-25.