Ferocactus townsendianus is a solitary-stemmed barrel cactus with short-cylindric to slightly conical stems, usually to 50 cm (20 in) tall but sometimes to 1 m (3.3 ft).

[2][3][5] Ferocactus townsendianus was described by Nathaniel Lord Britton and Joseph Nelson Rose in their third volume of The Cactaceae in 1922.

The type specimen was collected on Isla San José by Rose in March 1911 while visiting the Gulf of California on the USS Albatross.

[2] The specific epithet is named in honor of Charles H. Townsend, the director of the New York Aquarium, who was in charge of the scientific work of the Albatross when the ship was in the waters of the Baja California Peninsula, when Rose discovered the plant.

It ranges from the vicinity of Loreto and San Juanico to the southern Sierra de la Giganta and south into the Cape region.