San Luis, CO
The Town of San Luis is a statutory town that is the county seat and the most populous town of Costilla County, Colorado, United States. The population was 739 at the 2000 census.
Hispanic settlers from the Taos Valley established several small villages along the Rio Culebra in the San Luis Valley and officially took possession of this portion of the Sangre de Cristo Land Grant on April 9, 1851. Settlers built a church in the central village of La Plaza Medio and dedicated it on the Feast of Saint Louis, June 21, 1851. The village was renamed San Luis de la Culebra in honor of its patron saint. San Luis remained part of the Territory of New Mexico until 1861 when the Territory of Colorado was established. Today, San Luis is the oldest town in the State of Colorado.
The town of San Luis lies within the San Luis Valley at 37°12′7″N 105°25′20″W / 37.20194°N 105.42222°W / 37.20194; -105.42222 (37.201988, -105.422360).