This layer shows the spatial extent of principal aquifers in Maryland, classified by aquifer name and type. Aquifer units include the Columbia aquifer, Chesapeake group, Aquia aquifer, Magothy aquifer, Potomac group, Piedmont and Blue Ridge crystalline aquifers, Carbonate aquifers, Newark group, Appalachian sedimentary aquifers, and areas not designated as a principal aquifer.
The data is sourced from the U.S. Geological Survey (USGS) and was digitized using georeferencing techniques applied to a USGS map image. It is intended to support groundwater resource assessment and aquifer characterization across the state, and can be used in conjunction with related datasets such as observation well locations and water-level records.