Dots show county records; shaded area shows likely general distribution.
Computer-generated distribution map, produced from records in a database available on this site.

Records of G. firmus west of the Georgia-Alabama line may be G. pennsylvanicus instead. These two species hybridize in the Northeast (Harrison and Bagdanowicz 1997), and their relationships have not been studied along their presumed contact zone in Alabama, Mississippi, Louisiana, and Texas.

(Note: Monroe County, Florida, includes the southwest portion of the tip of mainland Florida and the upper and lower keys. These three parts of that county are mapped separately in the "dot maps" but not in the computer-generated distribution maps, which are strictly at the county level.)