The specific name hammondii is in honor of William A. Hammond, the U.S. Army surgeon who collected the first specimens.

[3][4] T. hammondii is a medium-sized snake, 18–30 in (46–76 cm) in total length (including tail), with a head barely wider than the neck.

The checkered variant lacks the lateral stripes and has two rows of small dark spots on each side.

[5] The two-striped garter snake is found in western North America, ranging from central California to Baja California, Mexico.

It is a highly aquatic species, and prefers habitat adjacent to permanent or semi-permanent bodies of water.