The eastern ratsnake, Pantherophis alleghaniensis, is found in the United States east of the Apalachicola River in Florida, east of the Chattahoochee River in Georgia, east of the Appalachian Mountains, north to southeastern New York and western Vermont, eastern Pennsylvania, Maryland, South Carolina, North Carolina, Georgia, south to the Florida Keys. In the Florida Panhandle, it readily hybridizes with the gray rat snake (Pantherophis spiloides).
Adults are shiny black dorsally, with a cream or white chin and throat. The belly has an irregular black and white checkerboard pattern, becoming uniformly slate gray towards the tail. Juveniles have dark dorsal blotches on a grayish ground color.