Tesnus is a ghost town and unincorporated community in Brewster County, in the U.S. state of Texas.

Locally, its shales contain carbonaceous plant fragments and spores and some of its sandstone beds contain wood casts up to 30 cm (12 in) long.

Rare fossils of conodonts, radiolaria, sponge spicules, a crustacean, and inarticulate brachiopods have also been found in the Tesnus Formation.

[5] The sediments comprising the Tesnus Formation accumulated within deep sea submarine fan and channel complexes.

These sediments came dominantly from the southeast, likely from an approaching continental terrane that later collided with North America during the Ouachita orogeny.