From OpenwaterpediaSea of Cortez or Gulf of California or Sea of Cortés or Vermilion Sea or Mar de Cortés or Golfo de California is a body of water that separates the Baja California Peninsula from the Mexican mainland. It is bordered by the states of Baja California, Baja California Sur, Sonora, and Sinaloa with a coastline of approximately 2,500 mi (4,000 km). Rivers which flow into the Gulf of California include the Colorado, Fuerte, Mayo, Sinaloa, Sonora, and the Yaqui. The gulf's surface area is about 62,000 sq mi (160,000 km2). The name "Gulf of California" predominates on most maps in English today. The name "Sea of Cortés" or Mar de Cortés is the one preferred by most local residents.
The Gulf is thought to be one of the most diverse seas on the planet, and is home to more than 5,000 species of macro-invertebrates. Baja California itself is actually one of the longest, most isolated peninsulas in the world, second only to the Malay Peninsula in Southeast Asia.
It is a UNESCO World Heritage Site.