The Islas San Benito lie in the Pacific Ocean off the west coast of the Mexican state of Baja California, 25 km west of Cedros Island. They are part of the Cedros Island delegación, a subdivision of Ensenada municipality, Baja California.
The group consists of three barren islands, with a total area of 3.899 km² and is surrounded by rocks and patches of kelp.
The census of 2001 recorded a population of two on Benito del Oeste (West Benito); the other islands are uninhabited.
The vegetation consists mainly of low shrubs and herbs as well as some large cacti. There are few land animals and no native mammals. Birds are moderately abundant due to the islands' barrenness.