Well-construction, geologic, and water level data from 1978 to 1985 were compiled for 163 sites near Blackfoot, Idaho. Groundwater quality data were compiled for 51 sites for the period 1961-83 and for 54 sites for the period 1984-85. Data were collected in support of the hydrologic and water quality components of the U.S. Geological Survey 's groundwater contamination investigation near Blackfoot. Result of the investigation are presented in an interpretive report, published separately.