“Kentucky’s venomous snakes are the copperhead, cottonmouth, timber rattlesnake, and pigmy rattlesnake. All four species belong to a group of snakes called pit vipers.” KDFWR
Size
Typically 30 to 48 inches (about 3 to 4 feet); recorded up to 75 inches.
How to recognize it
Heat-sensing pit between nostril and eye; no rattle
Head much wider than the neck, with a dark bar from the eye to the jaw; vertical (cat-eye) pupils
Gapes to show the white lining of its mouth when threatened
Where in Kentucky
Physiographic Regions: Interior Plateau, Interior River Valley And Hills, Mississippi Alluvial Plain, Mississippi Valley Loess Plain KDFWR
Conservation
KY SWAP 2023 Species of Greatest Conservation Need; priority group: High; state rank S3
What the sources say
Venom: “Venomous - Species with the "" icon indicate that this species is venomous; please use caution when encountering this species.) … of the 32 types of snakes found in Kentucky, only four are venomous. … [species card:] NORTHERN COTTONMOUTH (Agkistrodon piscivorus leucostoma)” (KDFWR)
Habitat: Generally requires high south or west facing wooded bluffs providing mammal burrows and/or other underground retreats for successful hibernation. (KDFWR)
Seen from directly above, a watersnake's eyes are visible but a cottonmouth's are not. Watersnakes have round pupils and no facial pit, and they usually have thin dark vertical lines on the lips.
Alabama DCNR says this snake is often confused with the cottonmouth. TWRA: the diamond-backed watersnake is lighter, with a chain-like pattern; watersnakes in general lack the cottonmouth's facial pits (see the watersnake entry above).
On young cottonmouths the dark crossbands have many dark spots and speckles; copperhead bands have none or one. Adult copperheads keep the banded pattern, while adult cottonmouths are usually plain and dark. A cottonmouth's eye is hidden in a dark facial band; a copperhead's is not.
Kentucky Snakes (booklet). Kentucky Department of Fish and Wildlife Resources (KDFWR). archived copy, captured January 21, 2015; checked November 3, 2026.Quoted passages (2)
“The cottonmouth has a limited distribution in Kentucky.”
“Kentucky’s venomous snakes are the copperhead, cottonmouth, timber rattlesnake, and pigmy rattlesnake. All four species belong to a group of snakes called pit vipers.”
Snakes (Snakes of Kentucky). Kentucky Department of Fish and Wildlife Resources (KDFWR). archived copy, captured August 27, 2025; checked November 3, 2026.Quoted passages (2)
“Venomous - Species with the "" icon indicate that this species is venomous; please use caution when encountering this species.) … of the 32 types of snakes found in Kentucky, only four are venomous. … [species card:] NORTHERN COTTONMOUTH (Agkistrodon piscivorus leucostoma)”
“However, the state has never stocked rattlesnakes in Kentucky.”
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