Hydrologic data were collected in early 1985 from the northern part of the Hueco Bolson in Dona Ana County, New Mexico, and El Paso County, Texas, and in adjacent areas in the Tularosa Basin in New Mexico. Water-level measurements made in 50 wells are presented in this report. Information is also presented on groundwater withdrawals from the Hueco Bolson by El Paso and Ciudad Juarez municipal wells, by industrial and military wells, and by wells in the Chaparral, New Mexico, area that have been used for both irrigation and municipal purposes. Lithologic logs and geophysical logs are included for four test wells that were drilled as part of this project during August and September 1985. (USGS)