This dataset includes the locations of magnetotelluric (MT) stations collected in 2006 in the Southern San Luis Valley, Colorado. The U.S. Geological Survey conducted a series of multidisciplinary studies, including MT surveys, in the San Luis Valley to improve understanding of the hydrogeology of the Santa Fe Group and the nature of the sedimentary deposits comprising the principal groundwater aquifers of the Rio Grande rift. The shallow unconfined and the deeper confined Santa Fe Group aquifers in the San Luis Basin are the main sources of municipal water for the region. The population of the San Luis Valley region is growing rapidly and water shortfalls could have serious consequences. Future growth and land management in the region depend on accurate assessment and protection of the region's groundwater resources.