The Gulf of California (also called Sea of Cortez or Sea of Cortés; and nearby is known in the Spanish language as Mar de Cortés or Mar Bermejo or Golfo de California) is an area of water that is in between the Baja California Peninsula and Mexican mainland. It is surrounded by the states of Baja California, Baja California Sur, Sonora, and Sinaloa. The name "Gulf of California" is on most maps in English today. The name "Sea of Cortés" is the one preferred by local people. Francisco de Ulloa named it for Hernán Cortés, who sent him to explore the coast. 