San Diego Bay from Cabrillo National Monument, Point Loma, San Diego, California (75)
San Diego Bay is a natural harbor and deepwater port located in San Diego County, California near the US-Mexico border. The bay, which is 12 miles (19 km) long and 1 to 3 miles (1.6 to 4.8 km) wide, is the third largest of the three large, protected natural bays on California's entire 840 miles (1,350 km) long coastline after San Francisco Bay and Humboldt Bay. The highly urbanized land adjacent to the bay includes the city of San Diego (eighth largest city in the United States) and four other cities, including National City, Chula Vista, Imperial Beach and Coronado.
Considered to be one of the best natural harbors on the west coast of North America, it was colonized by Spain beginning in 1769. Later it served as base headquarters of major ships of the United States Navy in the Pacific until just before the United States entered World War II, when the newly organized United States Pacific Fleet primary base was transferred to Pearl Harbor, Hawaii. However, San Diego Bay remains as a home port of major assets, including several aircraft carriers, of the United States Pacific Fleet, and as a result of base closures beginning in the 1980s, facilities in San Diego Bay are the only remaining major naval base facilities still in operation in the entire State of California.