The Mt. Simon-Hinckley aquifer is the deepest bedrock aquifer in south-central/southeastern Minnesota, including the Minneapolis-St. Paul metro area. The aquifer is often overlain by sand and gravel, and bedrock aquifers which provide ample groundwater. The margins of the Mt. Simon-Hinckley aquifer have been identified as areas of focused recharge. Near the margins, the Mt. Simon-Hinckley aquifer may be the only available groundwater source. State statutes limit present use, protecting the aquifer as last resort for the future.