This report provides most of the data in the files of the U.S. Geological Survey on the quality of groundwater in Kentucky. All analyses through 1979 are included except for some special purpose repetitive analyses and some with a very limited number of constituents. County location maps are included with the analyses. These include location, distribution, and density of sampling sites in each county. Most of the data in this report resulted from cooperative studies made with the Kentucky Geological Survey and with other Federal, State, and local agencies. (USGS)