The Western Interior Plains aquifer system is located in parts of Arkansas, Colorado, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming and covers an area of more than 220,800 square miles. The thickness of the aquifer system ranges from 500 feet in eastern Colorado (HA 730-D) to as much as 10,000 feet in western Oklahoma (PP_1414B). This aquifer system consists of water-bearing dolostone, limestone, and shale and overlies the basement confining unit in the western part of the Interior Plains physiographic division. This aquifer system consists of the upper aquifer unit (A1), a middle confining unit, and the lower aquifer unit (A2). The aquifer system is overlain by the Western Interior Plains confining system and is underlain by the Basement confining unit (PP_1414B). This product provides source data for the Western Interior Plains aquifer system framework, including: Georeferenced images: 1. i_63WIP_A1_top.tif: Digitized figure of extent and altitude contour lines representing the top of the Western Interior Plains aquifer system upper unit. The original figure was from PP_1414B plate 6. 2. i_63WIP_A1_bot.tif: Digitized figure of altitude contour lines of the top of the confining unit between the upper and lower units of the Western Interior Plains aquifer system. This figure was used to construct the bottom contour lines of the upper aquifer unit. The original figure was from PP_1414B plate 5. 3. i_63WIP_A2_top.tif: Digitized figure of extent and altitude contour lines representing the top of the Western Interior Plains aquifer system lower unit. The original figure was from PP_1414B plate 4. 4. i_63WIP_A2_bot.tif: Digitized figure of altitude contour lines of the top of the basement confining unit of the Western Interior Plains aquifer system. This figure was used to construct the bottom contour lines of the lower aquifer unit. The original figure was from PP_1414B plate 3. Extent shapefiles: 1. p_63WIP.shp: Polygon shapefile containing the areal extent of the Western Interior Plains aquifer system sourced from PP_1414B plates 4 and 6. The extent file contains the upper and lower subunits A1 and A2. Contour line shapefiles: 1. c_63WIP_A1_top.shp: Contour line dataset containing altitude values, in feet reference to National Geodetic Vertical Datum of 1929 (NGVD29), of the top of the Western Interior Plains aquifer system upper unit. These data were used to create the ra_63WIP_A1_top.tif dataset. 2. c_63WIP_A1_bot.shp: Contour line dataset containing altitude values, in feet reference to NGVD29, of the bottom of the Western Interior Plains aquifer system upper unit. These data were used to create the ra_63WIP_A1_bot.tif dataset. 3. c_63WIP_A2_top.shp: Contour line dataset containing altitude values, in feet reference to NGVD29, of the top of the Western Interior Plains aquifer system lower unit. These data were used to create the ra_63WIP_A2_top.tif dataset. 4. c_63WIP_A2_bot.shp: Contour line dataset containing altitude values, in feet reference to NGVD29, of the bottom of the Western Interior Plains aquifer system lower unit. These data were used to create the ra_63WIP_A2_bot.tif dataset. Altitude raster files: 1. ra_63WIP_A1_top.tif: Altitude raster dataset of the top of the Western Interior Plains aquifer system upper unit. The altitude values are in meters reference to North American Vertical Datum of 1988 (NAVD88). This raster was interpolated from contour line shapefile c_63WIP_A1_top.shp. 2. ra_63WIP_A1_bot.tif: Altitude raster dataset of the bottom of the Western Interior Plains aquifer system upper unit. The altitude values are in meters reference to NAVD88. This raster was interpolated from contour line shapefile c_63WIP_A1_bot.shp. 3. ra_63WIP_A2_top.tif: Altitude raster dataset of the top of the Western Interior Plains aquifer system lower unit. The altitude values are in meters reference to NAVD88. This raster was interpolated from contour line shapefile c_63WIP_A2_top.shp. 4. ra_63WIP_A2_bot.tif: Altitude raster dataset of the bottom of the Western Interior Plains aquifer system lower unit. The altitude values are in meters reference to NAVD88. This raster was interpolated from contour line shapefile c_63WIP_A2_bot.shp. Depth raster files: 1. rd_63WIP_A1_top.tif: Depth raster dataset of the top of the Western Interior Plains aquifer system upper unit. The depth values are in meters below land surface (NED, 100-meter). 2. rd_63WIP_A1_bot.tif: Depth raster dataset of the bottom of the Western Interior Plains aquifer system upper unit. The depth values are in meters below land surface (NED, 100-meter). 3. rd_63WIP_A2_top.tif: Depth raster dataset of the top of the Western Interior Plains aquifer system lower unit. The depth values are in meters below land surface (NED, 100-meter). 4. rd_63WIP_A2_bot.tif: Depth raster dataset of the bottom of the Western Interior Plains aquifer system lower unit. The depth values are in meters below land surface (NED, 100-meter).