The Golden Gate is the North American strait connecting San Francisco Bay to the Pacific Ocean. Since 1937 it has been spanned by the Golden Gate Bridge. Technically, the 'gate' is defined by the headlands of the San Francisco Peninsula and the Marin Peninsula, while the 'strait' is the water flowing in between.

During the last Ice Age, when sea level was several hundred feet lower, the waters of the glacier-fed Sacramento River and the San Joaquin River scoured a deep channel through the bedrock on their way to the ocean. The strait is well known today for its depth and powerful tidal currents from the Pacific Ocean. Many small whirlpools and eddies can form in its waters.

Before the arrival of Europeans in the 18th century, the area around the strait and the bay was inhabited by the Ohlone to the south and Coast Miwok people to the north. Descendants of both tribes remain in the area.

The Golden Gate is often shrouded in fog. During the summer, the heat in the California Central Valley causes the air there to rise. This can create strong winds which pull cool moist air in from over the ocean through the break in the hills caused by the Golden Gate, commonly causing a stream of dense fog to enter the bay. The strait was surprisingly elusive for early European explorers, presumably due to this persistent summer fog. The strait is not recorded in the voyages of Juan Rodriguez Cabrillo nor Francis Drake, both of whom may have explored the nearby coast in the 16th century in search of the fabled Northwest Passage. The strait is also unrecorded in observation by Spanish galleons returning from the Philippines that laid up in nearby Drakes Bay. These galleons rarely passed east of the Farallon Islands (27 miles west of the Golden Gate), fearing the possibility of rocks between the Islands and the mainland.