The Gulf of California, also known as the Sea of Cortez or the Sea of Bermejo, is an extension of the Pacific Ocean that is located between the Baja California Peninsula and the states of Sonora and Sinaloa in Northeast Mexico. It is 1,126 km (705 miles) long and its width varies from 48 km (30 miles) to 241 km (150 miles). The mouth of the Colorado River is located at the northernmost tip. The islands listed below are located within the Gulf: Isla Ángel de la Guarda, Montague, Gore, Consag, El Huerfanito, Miramar, Coloradito, Encantada, Pómez, San Luis, Mejía, Granitos, Navío, Pelícano, Alcatraz, Coronadito , Smith, Pond and the islands and islets located within Bahía de los Ángeles.

The Sea of Cortez is home to 36 species of mammals, 31 cetaceans, five of the seven existing sea turtles in the world, more than 700 species of fish including sharks, 210 birds and a little more than 6,000 species of macro invertebrates, including some of the most beautiful nudibranchs in the world.

The Sea of Cortez is home to an immense concentration of microorganisms and an extraordinary biodiversity thanks to its abundant light and nutrient-rich water. These components, together with its crystal clear waters, led the Oceanographer Jacques Ives Cousteau to call it:

The seabed of the Sea of Cortez is one of the roughest in the world.