- Roswell (/ˈrɒzwɛl/) is a city in and the seat of Chaves County, New Mexico, United States. The population was 48,422 at the 2020 census, making it the fifth-most populous city in New Mexico. It is home of the New Mexico Military Institute (NMMI), founded in 1891. The city is also the location of an Eastern New Mexico University campus. Bitter Lake National Wildlife Refuge is located a few miles northeast of the city on the Pecos River. Bottomless Lakes State Park is located 12 miles (19 km) east of Roswell on US 380. Chaves County forms the entirety of the Roswell micropolitan area.