The ODNR Division of Geological Survey’s extensive collection of geologic data is available for interactive viewing and download using the Ohio Geology Interactive Map. This online map service is a robust tool for researching the state's geologic history, structure, and materials. It is provides desktop and mobile users a way to create custom geologic maps of their areas of interest. It also serves as a way to view and interact with geologic GIS data prior to downloading it. Have questions? Check out the information below for some explanation of map features and useful links.
Using the Map
Click the green LAUNCH button on this page to access the Ohio Geology Interactive Map. After reviewing the pop-up window, a map showing the bedrock geology of Ohio will appear (see image at top of this page).
Searching an Area of Interest
Zoom to an area of interest or search by address. To zoom in, either spin the mouse wheel or click the + symbol (1) in the upper left corner of the map viewer. Use the "County Bookmarks" tool (2) on the left side of the screen to zoom to a county of interest. To search by address, click "Other Tools" (3) on the left side of the screen, enter the property address or coordinates in the box that appears, and hit the Enter key.
Viewing & Changing Data Layers, Base Maps
Different geologic data can be viewed by toggling on/off the various categories under “Legends & Layers” (4) on the left side of the screen. Be sure to place check marks next to any data layers you wish to see, and leave blank those that you do not want to see. Note: Each data layer (and their larger groupings) will need to be checked for them to show up on the map.
Change the base map to show satellite imagery or a topographic map by clicking the “Basemaps” button in the top right corner of the map.
Boundaries for USGS 7.5-minute and 30x60-minute quadrangles may be turned on/off.
- Quadrangle 24K (7.5 minute): Divides Ohio into 788 areas; the most detailed geology maps are commonly at this scale. Click here for index.
- Quadrangle 100K (30-x-60 minute): Divides Ohio into 34 areas. Click here for index.
Geology Data Layers
This layer depicts the uppermost consolidated rock below the land surface.
- Structure lines: Structural features of the bedrock, such as faults.
- Bedrock geology 24K: Detailed bedrock map of Ohio. Click here to download detailed geologic unit descriptions (pdf).
- Bedrock geology 500K: Generalized bedrock map of Ohio.
- Bedrock topography: Elevation of the top of the bedrock surface above sea level. Often below the ground surface and buried by glacial material.
- Precambrian faults: Deep faults in the ancient crystalline basement rock.
- Precambrian 100-ft contours: Elevation (relative to sea level) of the top of the deep, ancient Precambrian rock.
Bedrock Geology Layer
This layer depicts unconsolidated glacial deposits on top of the bedrock.
- Glacial boundary: Maximum extent of the two most recent major glacial advances across Ohio
- Quaternary geology 500K: Generalized glacial geology of Ohio.
- Surficial stack map 24K: Detailed surficial geology of Ohio. Describes the nature and thicknesses of Ohio’s glacial deposits and surficial materials.
- Drift thickness: The thickness of unconsolidated glacial gravel, sand, silt, or clay. Drift thickness maps are made by subtracting the elevation of the bedrock from the elevation of the ground surface.
Surficial Geology Layer
Several layers depict natural and human-made features that may threaten Ohioans and/or their property.
Earthquakes – Includes earthquakes instrumentally recorded and those that occurred and were documented prior to the advent of seismometers.
- Ohio seismic stations – All of the seismometers that make up the Ohio Seismic Network (OhioSeis).
- Earthquake epicenters – Locations of recent and historic earthquakes.
Earthquake Epicenters Layer
Karst – Karst includes dissolution features, such as sinkholes—depressions that are generally dry, drain into bedrock fractures, and may have an active throat and exposed bedrock.
- Karst Data Points: The deepest point in a sinkhole, or the location of the sink throat.
- Karst Depressions Depth in Feet: Generally, a shallow bowl or funnel-shaped area representing the extent of a sinkhole.
- Karst Geology of Ohio: Generalized bedrock geology that may contain sinkholes. Sinkholes are commonly found in carbonate rock where the glacial drift is less than 20 ft thick.
- Karst Detailed Mapping Completed Areas: These boundaries indicate the extent of where detailed karst mapping projects have been completed.
Abandoned Underground Mines (AUMs)
- AUM-Mine Points: Points showing mine locations.
- AUM-Point Location: Additional mine point locations.
- AUM-Known: Polygons showing extents of known mines.
- AUM-Partially Known: Polygons showing extents of partially known mines.
Coastal Erosion Areas – Areas along Ohio's Lake Erie shoreline that have been periodically examined for erosion.
Industrial Minerals & Coal Geology
This layer depicts locations and thicknesses for the coal resources of Ohio.
- Counties with mines: Counties that presently have or historically have had at least one underground mine.
- Coal elevation: Maps of various coal seam elevations above sea level.
- Coal thickness: Thickness of respective coal seam.
Ohio Coal Isopach (Thickness) Layer
This layer depicts water resources found in the bedrock and surficial/glacial materials (aquifers) of Ohio
- Water wells: Includes both public and private well logs across Ohio; useful for subsurface investigation and includes total depth, water quality, and materials drilled through.
- Potentiometric surface unconsolidated: Direction and gradient of groundwater flow in surficial/glacial materials.
- Potentiometric surface consolidated: Direction and gradient of groundwater flow in bedrock.
- Statewide consolidated aquifers: Delineates Ohio's bedrock aquifers, providing information on geologic units and potential groundwater yield.
- Statewide unconsolidated aquifers: Describes Ohio's surficial/glacial aquifers, providing details on aquifer names, hydrogeological settings, thicknesses, and potential well yields.
- Groundwater vulnerability: Includes data for hydrogeologic settings, DRASTIC paramaeters, and vulnerability indexes.
Ohio Water Wells Layer