city, northern Portugal. It lies along the Tâmega River, north-northeast of Vila Real town. The city, 5 miles (8 km) south of the Spanish frontier, is the site of a spa, the Chaves thermal springs, known as Aquae Flavius to the Romans, who fortified it. Chaves was later dominated successively by the Suebi, Visigoths, Arabs, and Spanish. Roman remains include a fully functioning 16-arch bridge and two inscribed columns. There are several notable medieval churches and a castle of the dukes of Bragança. An agricultural and textile centre, Chaves is also known for its smoked ham. An anthropological institute is located in the city. Pop. (2005 est.) 44,298.

county, southeastern New Mexico, U.S. Most of Chaves county lies in the Great Plains, with the extreme western section including the Guadalupe and Sacramento Mountains and a portion of the Lincoln National Forest. On the east lies Mescalero Ridge. In the flat-to-rolling Pecos River valley are Bitter Lake National Wildlife Refuge and Bottomless Lakes State Park. The county is scarred with dry creek beds, lakes, and reservoirs; the Pecos River flows southward through the centre.

By the 16th century the region was home to nomadic Jumanos Indians, who lived by hunting buffalo, but by the mid-19th century it was the domain of Apaches. The expeditions of Antonio de Espejo (1583) and Gaspar Castáño de Sosa (1590) passed along the Pecos. Irrigation farming began in 1880; the 1891 discovery of an artesian basin beneath the county led to its development as one of New Mexico's leading agricultural areas (cattle, milk, hay, cotton). Chaves county was established in 1889.

While Walker Air Force Base operated there (1941–68), the U.S. government was a major element in the county's economy. Since then oil and natural-gas extraction, health care, retail and wholesale trade, and manufacturing (motor-vehicle bodies, food, clothing), centred in the city of Roswell, the county seat, have been its economic bases. Area 6,071 square miles (15,725 square km). Pop. (2000) 556,678; (2007 est.) 629,292.