It is a nonvenomous, colubrid snake that inhabits coastal salt marshes and brackish estuaries along the coast of the Gulf of Mexico from Florida to Texas.

[3] The color pattern in this subspecies is variable, but adults tend to have a dorsum that ranges from dark gray to reddish-brown with four yellowish longitudinal stripes down the body, two on each side.

[2][3] The Gulf salt marsh snake reaches sexual maturity at three years.

Females give birth to 2-44 live young that range from 17.7 to 22.8 centimetres (7.0 to 9.0 in) in total length.

[2][3] N. c. clarkii is primarily nocturnal, preying upon small fish, crabs, shrimp, and other invertebrates that become trapped in tidal pools during low tide.