This digital GIS dataset and accompanying nonspatial files synthesize model outputs from a regional-scale volumetric 3D geologic model that portrays the generalized subsurface geology of the Michigan Basin region of Michigan, Wisconsin, Illinois, Indiana, and Ohio. The intent of this product is to rapidly and efficiently synthesize large quantities of geologic data from a wide variety of sources into a multi-use geologic framework model applicable to natural resource exploration and management. Major geographic features within the study area include Lake Michigan and the Lower Peninsula of Michigan, and portions of the Upper Peninsula of Michigan, Lake Huron, Lake Saint Clair, and Lake Erie. Geologically, the study area incorporates major structures such as the Kankakee Arch, Findlay Arch, Wisconsin Arch, Algonquin Arch, Lake Superior Syncline, and the broader Michigan sedimentary basin from the Precambrian basement to the Earth's surface. Data released here consists of stratigraphic horizon grids of major Phanerozoic sedimentary units that broadly define the geometry of the subsurface, a stratigraphic horizon grid of the uppermost Precambrian basement rocks, and line data that estimate the two-dimensional geometry of fault planes that intersect stratigraphic horizon grids. The presence of folds and unconformities are implied by the 3D geometry of the stratigraphic units, but these are not included as discrete features in this data release. The 3D geologic model was constructed from a wide variety of private and public surface and subsurface geologic data; none of these input data are part of this data release, but data sources are thoroughly documented such that a user could obtain these data from other sources if desired. The MichiganBasin3D geodatabase contains 41 subsurface stratigraphic horizons in raster format, representing the tops of modeled subsurface units, as well as a feature dataset titled "GeologicModel." This feature dataset includes a line feature class of 180 fault segments that delineate faults with probable post-Precambrian offset extending into the Phanerozoic sedimentary layers (PrecambrianLevelFaults_Throughgoing). It also features a line class of 170 fault segments representing throughgoing faults at the level of the top Trenton Group (TrentonLevelFaults), along with a polygon feature class delineating the study area (ModelBoundary). Nonspatial tables provide definitions of data sources (DataSources), terminology used in the dataset (Glossary), and descriptions of the modeled surfaces (DescriptionOfModelUnits). Additional file folders contain vector data in shapefile format, raster data in ASCII format, and tables in comma-separated values format. A comprehensive data dictionary outlines the entity and attribute information for all geospatial data and accompanying nonspatial tables (EntityAndAttributes). Accompanying this data release is a workbook “MichiganBasinInputSummaryTable.csv”, which tabulates the stratigraphic horizons modeled in each fault block, and the types and quantity of data inputs for each stratigraphic horizon. Key references associated with each data input are found in the "MichiganBasinInputReferences" so any user could replicate this work if they desired. An associated USGS report: “A three-dimensional geologic framework model of the Michigan Basin region, Illinois, Indiana, Michigan, Ohio, and Wisconsin, USA” documents the process of manipulating and interpreting surface and subsurface geologic data to create the model. It additionally contains critical information about model units, and uncertainty regarding their ability to predict true ground conditions.