Costilla County is located in the south-central region of Colorado. It is the ninth-least populous of the 64 counties in the state. The county seat is San Luis, the oldest town in Colorado.

Costilla County is governed by a three-member Board of County Commissioners. The county is divided into three districts, each represented by one commissioner. The county is also served by a county administrator, a county attorney, a county treasurer, a county clerk and recorder, a county assessor, and a county sheriff.

The county is home to several state parks, including the Great Sand Dunes National Park and Preserve, the San Luis State Wildlife Area, and the Rio Grande National Forest. The county is also home to several historic sites, including the San Luis People's Ditch, the oldest irrigation ditch in Colorado, and the San Luis People's Church, the oldest church in Colorado.

Costilla County is served by several school districts, including the San Luis Valley School District, the Centennial School District, and the Costilla County School District. The county is also home to several higher education institutions, including Adams State University, Colorado State University-Pueblo, and Trinidad State Junior College.

For the most up-to-date and in-depth information, please check the public records links below.