Since 1972 the U.S. Geological Survey has been conducting a series of field evaluation studies in southeastern New Mexico for the Waste Management Division of the Department of Energy (formerly U.S. Energy Research and Development Administration). On the basis of these studies, a tentative site for a nuclear waste repository/disposal facility has been selected near the center of the Los Medafios area in Eddy and Lea Counties, New Mexico (Fig. 1). The proposed host rock for the emplacement of nuclear waste at the potential repository site consists of the bedded evaporite deposits of the Salado Formation. Numerous test holes have been drilled in the Los Medafios area to determine geologic conditions and to obtain geophysical data and rock samples for additional site-evaluation studies. This report tabulates borehole gravity data acquired in one of these test holes, ERDA No. 9, and summarizes the geology of the consolidated rock formations in which gravity observations were made.