In 2012, the U.S. Geological Survey, in cooperation with the Kickapoo Tribe of Oklahoma, compiled historical groundwater-quality data collected from 1948 to 2011 and water-well completion information in parts of Lincoln, Oklahoma, and Pottawatomie Counties in central Oklahoma to support the development of a comprehensive water-management plan for the Tribe's jurisdictional area. In this study, water-quality data from 155 water wells, collected from 1948 to 2011, were retrieved from the U.S. Geological Survey National Water Information System database; these data include measurements of pH, specific conductance, and hardness and concentrations of the major ions, trace elements, and radionuclides that have Maximum Contaminant Levels or Secondary Maximum Contaminant Levels in public drinking-water supplies.