Pantherophis alleghaniensis, commonly called the eastern ratsnake, is a nonvenomous colubrid species endemic to North America.
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. The ventral pattern in juveniles is the same as in adults. The eyes are round with a black pupil, and particularly in juveniles but not always present in adults, a distinct white margin.
The yellow morph of the eastern ratsnake, Pantherophis alleghaniensis ssp. quadrivittata, is sometimes called the yellow ratsnake or the Florida ratsnake.