Colorado
Snakes in Boulder County
11 species have been documented here, 1 of them venomous.
Venomous snakes in Boulder County
Full guide & what to do if bitten →
Prairie RattlesnakeCrotalus viridisVenomousHeavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
Every snake recorded in Boulder County
Gopher Snake
Pituophis catenifer
Harmless
Western Terrestrial Garter Snake
Thamnophis elegans
Harmless
Plains Garter Snake
Thamnophis radix
Harmless
Prairie Rattlesnake
Crotalus viridis
Venomous
North American Racer
Coluber constrictor
Harmless
Common Garter Snake
Thamnophis sirtalis
Harmless
Common Watersnake
Nerodia sipedon
Harmless
Western Milksnake
Lampropeltis gentilis
Harmless
Plains Black-headed Snake
Tantilla nigriceps
Harmless
Smooth Greensnake
Opheodrys vernalis
Harmless
Lined Snake
Tropidoclonion lineatum
Harmless
Compiled from verified GBIF & iNaturalist observations. Informational only.
Snakes in Boulder County: FAQ
- Are there venomous snakes in Boulder County, Colorado?
- Yes. 1 venomous snake species has verified records in Boulder County, Colorado, including Prairie Rattlesnake. Most snakes in Boulder County, Colorado, however, are harmless.
- How many snake species live in Boulder County, Colorado?
- 11 snake species have verified records in Boulder County, Colorado, of which 1 is venomous.
- What is the most commonly seen snake in Boulder County, Colorado?
- The Gopher Snake is the most frequently reported snake in Boulder County, Colorado, based on verified wildlife observations.
- What should I do if I see a venomous snake in Boulder County, Colorado?
- Keep your distance and do not try to catch or kill it. Most bites happen when people handle or corner a snake. If someone is bitten, contact local emergency services or poison control immediately.