From 1950 to the present date the Ground Water Branch, U.S. Geological Survey, has been collecting data about the ground-water supply in the Sells area, at the request of the Bureau of Indian Affairs, Papago Indian Agency. The purpose of these studies has been to aid in locating and developing additional ground-water supplies for the community of Sells, the agency headquarters. The work has been financed by and has been in cooperation with the Papago Indian Agency. In addition to the author of this memorandum, the following personnel aided in collecting data: D. G. Metzger, H. E. Skibitzke, S.F. Turner, H. N. Wolcott, and C. B. Yost, Jr.