This data release includes text files of well data and shapefiles of potentiometric contours of the Fort Union, Hell Creek, and Fox Hills aquifers within the Standing Rock Indian Reservation. The data accompanies a USGS scientific investigations map from Anderson and Lundgren (2024). The Standing Rock Sioux Tribe (the Tribe) and the U.S. Geological Survey (USGS) completed a comprehensive assessment of groundwater resources within the Standing Rock Indian Reservation.Generalized potentiometric surfaces of the Fort Union, Hell Creek, and Fox Hills aquifers were constructed to assess the groundwater resources of the Standing Rock Indian Reservation. Water-level data from the U.S. Geological Survey Groundwater Site Inventory (GWSI) database, the North Dakota Department of Water Resources (NDDWR), and the South Dakota Department of Agriculture and Natural Resources (SDDANR) were compiled and used to construct generalized potentiometric-surface maps representing average conditions of the Fort Union, Hell Creek, and Fox Hills Formations. The water-level measurements mean was used for wells with more than one water-level measurement. Recorded depth to water-levels were converted to hydraulic head by subtracting the water level from the land-surface elevation at the well location. Hydraulic-head values were spatially interpolated to create 2-dimensional potentiometric surfaces. The interpolated potentiometric surfaces were contoured using contour intervals of 50 ft and smoothed to correct for extreme changes in the potentiometric surfaces in areas of sparse data.