The U.S. Geological Survey provides a map showing areas that are potentially susceptible to natural sinkhole formation. Florida, the state with the most naturally occurring sinkholes, also provides a dedicated sinkhole Web page showing a sinkhole map and discussing the locations of former sinkholes within the Panhandle State.
The USGS karst map shows areas in the United States underlain with soluble subsurface rocks. The colored legends indicate the karst topography of a general area, including the type of karst terrain and the vertical extent of fissures, tubes and caves under a delineated location. The solution terrain in the northeastern Maine, western Massachusetts and western Vermont, for example, is generally made up of crystalline limestone and marbles. A number of small caves also run under the Berkshire Mountain and parts of western Vermont.
The map is originally from the Geological Information System. The delineated areas are generalized, and the potential sinkhole occurrence may still vary locally within each region.
The Florida Center for Instructional Technology of the University of Florida created the Florida sinkhole maps for 52 counties in the state. Each map shows a representation of the reported sinkhole events in each county based on data gathered from the Florida Department of Environmental Protection and the Florida Geological survey. Not all sinkhole events represented by the maps are karst-related subsidence, as some also occurred due to collapsed water mains, sewerage systems and other man-made features.