California
Snakes in Contra Costa County
17 species have been documented here, 2 of them venomous.
Venomous snakes in Contra Costa County
Full guide & what to do if bitten →
Western RattlesnakeCrotalus oreganusVenomousHeavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
Prairie RattlesnakeCrotalus viridisVenomousHeavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
Every snake recorded in Contra Costa County

Gopher Snake
Pituophis catenifer
Harmless

Western Rattlesnake
Crotalus oreganus
Venomous

Ring-necked Snake
Diadophis punctatus
Harmless

Common Sharp-tailed Snake
Contia tenuis
Harmless

California King Snake
Lampropeltis californiae
Harmless

Western Terrestrial Garter Snake
Thamnophis elegans
Harmless

Aquatic Garter Snake
Thamnophis atratus
Harmless

Striped Racer
Masticophis lateralis
Harmless

North American Racer
Coluber constrictor
Harmless

Eastern Kingsnake
Lampropeltis getula
Harmless

Northern Rubber Boa
Charina bottae
Harmless

Coast Night Snake
Hypsiglena ochrorhynchus
Harmless

Prairie Rattlesnake
Crotalus viridis
Venomous

Sierra Garter Snake
Thamnophis couchii
Harmless

Common Garter Snake
Thamnophis sirtalis
Harmless

Diamondback Watersnake
Nerodia rhombifer
Harmless

Long-nosed Snake
Rhinocheilus lecontei
Harmless
Compiled from verified GBIF & iNaturalist observations. Informational only.
Snakes in Contra Costa County: FAQ
- Are there venomous snakes in Contra Costa County, California?
- Yes. 2 venomous snake species have verified records in Contra Costa County, California, including Western Rattlesnake, Prairie Rattlesnake. Most snakes in Contra Costa County, California, however, are harmless.
- How many snake species live in Contra Costa County, California?
- 10+ snake species have verified records in Contra Costa County, California, of which 2 are venomous.
- What is the most commonly seen snake in Contra Costa County, California?
- The Gopher Snake is the most frequently reported snake in Contra Costa County, California, based on verified wildlife observations.
- What should I do if I see a venomous snake in Contra Costa County, California?
- 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.