Chiasson and Lowe (1989) suggested the species be included in the genus Nerodia (watersnakes) due to its highly aquatic nature, however, this classification was later rejected based on genetic data.

[6][7][8] The scientific name Thamnophis rufipunctatus is a combination of Ancient Greek and New Latin that means "bush snake punctuated with red".

It is found in Arizona and New Mexico at or near the Mogollon Rim, mainly in canyon-bound headwaters of the Gila and San Francisco rivers and their tributaries.

[1] Narrow-headed garter snakes hibernate between October or November to March in rocky outcroppings above the flood line.

The FWS stated that population densities had notably declined and the snake was found in only 5 of 16 historical locations, though its status on tribal lands was unknown.

Additional threats include poisons intended to eliminate invasive species, drought, catastrophic wildfires, and possibly factors such as disease, siltation, killing and collection by humans, and overgrazing.

Fish and Wildlife Service for failing to implement proposed critical habitat after the species was listed as threatened.

[15] In October, 2021, the FWS designated 23,785 acres of critical habitat for the narrow-headed garter snake, including 447 miles of streams.