Hypsiglena is a genus of small, rear-fanged snakes, commonly referred to as night snakes, in the subfamily Dipsadinae of the family Colubridae.
Hypsiglena are found throughout the southwestern and western United States, from Texas and Kansas, west to California, north to Washington, and south into Mexico, as well as on islands off the coasts of Mexico.
The preferred habitat of night snakes is semiarid desert regions with rocky and sandy soils.
Night snakes typically do not exceed a total length (including tail) of 40 cm (16 in).
They are slender-bodied with a flattened head, and have small eyes with vertical pupils.