The Mission San José del Cabo was founded in 1730 on the west bank of the nearby Río San José. The Río San José flows into an estuary, the largest body of fresh water in southern Baja California Sur, after flowing largely underground for from its origin in the Sierra de la Laguna (Laguna Mountains). For more than 250 years it has furnished drinking and irrigation water for the town of San Jose del Cabo, beginning as a source of fresh water for Spanish galleons traveling back from the Philippines. The river used to flow above ground until the beginning of the 20th century due to anthropogenic causes. A one km long sand bar separates the estuary from what early Spanish explorers, including Sebastian Vizcaino, called the Bahía de San Bernabé or Bay of San Bernabé and now San José del Cabo Bay.