[2] Echinocereus maritimus is a cactus that forms cushions with up to 300 shoots, growing to 40 cm (16 in) high and 2 m (6 ft 7 in) in diameter.

The bright yellow, funnel-shaped flowers appear below the shoot tips, growing up to 6 cm (2.4 in) long and wide.

[3] Echinocereus maritimus is native to the west coast of Mexico's Baja California peninsula and nearby islands growing in coastal desert scrub at elevations between 0 and 50 meters.

Plants are found growing along with Euphorbia misera, Agave sebastiana, Bergerocactus emoryi, Lophocereus schottii, Myrtillocactus cochal, Ferocactus fordii, Cylindropuntia prolifera, Cochemiea pondii, Mammillaria brandegeei, and Cochemiea hutchisoniana subsp.

[4] First described as Cereus maritimus by Marcus Eugene Jones in 1883, the species was reclassified by Karl Moritz Schumann in 1897.