This geodatabase includes spatial datasets that represent the Texas Coastal Uplands and Mississippi Embayment aquifer system in the States of Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, and Texas. Included are: (1) polygon extents; datasets that represent the aquifer system extent, the entire extent subdivided into subareas or subunits, and any polygon extents of special interest (outcrop areas, no data available, areas underlying other aquifers, anomalies, for example), (2) raster datasets for the altitude of each aquifer subarea or subunit, (3) altitude, and/or if applicable, thickness contours used to generate the surface rasters, (4) georeferenced images of the figures that were digitized to create the altitude and thickness contours. The images and digitized contours are supplied for reference.

The extent of the Texas Coastal Uplands and Mississippi Embayment aquifer system is derived from the linework in the aquifer system extent maps in U.S. Geological Survey Professional Paper 1416-B (USGS PP 1416-B), plates 11, 13, 15, 16, and 17, and from a digital version of the aquifer extents presented in the U.S. Geological Survey Hydrologic Atlas 730, Chapters E and F.

The Texas Coastal Uplands and Mississippi Embayment aquifer system has 6 aquifer subunits, in order from the most surficial to the deepest: A1: Upper Claiborne aquifer, A2: Middle Claiborne aquifer, A3: Lower Claiborne- Upper Wilcox aquifer, A4: Middle Wilcox aquifer, A5: Lower Wilcox aquifer, A6: McNairy-Nacatoch aquifer.

The altitude and thickness contours for each available subunit were digitized from georeferenced figures of altitude contours in USGS PP 1416-B, and the resultant top and bottom altitude values were interpolated into surface rasters within a GIS using tools that create hydrologically correct surfaces from contour data, derives the altitude from the thickness (depth from the land surface), and merges the subareas into a single surface. The primary tool was an enhanced version of "Topo to Raster" used in ArcGIS, ArcMap, Esri 2014. The raster surfaces were corrected for the areas where the altitude of an underlying layer of the aquifer exceeded altitude of an overlying layer.