Marina del Rey is an unincorporated seaside community in Los Angeles County, California, with an eponymous harbor that is a major boating and water recreation destination of the greater Los Angeles area. The port is North America's largest man-made small-craft harbor and is home to approximately 5,000 boats. The area is a popular tourism destination for both land and water activities such as paddle board and kayak rentals, dining cruises, and yacht charters. Land activities include bicycling on several bicycle paths, walking paths along the waterfront, and birdwatching (birding). Wildlife watching opportunities include California sea lions and harbor seals. Dolphins and whales occasionally visit the deeper waters of harbor. This Westside locale is approximately 4 miles (6.4 km) south of Santa Monica, and 4 miles (6.4 km) north of Los Angeles International Airport, and 12.5 miles (20.1 km) west-southwest of Downtown Los Angeles.
The harbor is owned by Los Angeles County and managed by the Department of Beaches and Harbors (DBH), but the waters are environmentally regulated by state government and federal government through their many agencies and departments with overlapping oversight. The Los Angeles Times said in a 1997 editorial that the harbor is "perhaps the county's most valuable resource". The population was 8,866 at the 2010 census. For statistical purposes, the United States Census Bureau has defined Marina del Rey as a census-designated place (CDP). The census definition of the area may not precisely correspond to local understanding of the area with the same name.