Doña Ana County is a county located in the southern part of the State of New Mexico of the United States. As of the 2010 U.S. Census, its population was 209,233, which makes it the second-most populated county in New Mexico. Its county seat is Las Cruces, the second-most populous municipality in New Mexico, after Albuquerque with 102,926 as of the 2018 US Census estimate.
The county is named for Doña Ana Robledo, who died there in 1680 while fleeing the Pueblo Revolt. Doña Ana is pronounced Doh-nya Ahna. Doña Ana county is one of only two counties in the United States to have an accent mark in its name, the other being Coös County, New Hampshire.
Doña Ana County consists of the Las Cruces, NM Metropolitan Statistical Area, which is also included in the El Paso-Las Cruces, TX-NM Combined Statistical Area. It borders Luna, Sierra, and Otero counties in New Mexico, and El Paso County, Texas to the east and southeast.
The state of Chihuahua, Mexico borders the county to the south. Construction of an improved barrier on the border was expedited in 2019 with waivers of environmental and other laws. The waivers are for 27 laws including protection of endangered species, archaeological sites, and historic places.
