Seal Beach is a coastal city in Orange County, California, United States. As of the 2020 census, the population was 25,242, up from 24,168 at the 2010 census. Seal Beach is located in the westernmost corner of Orange County. To the northwest, just across the border with Los Angeles County, lies the city of Long Beach and the adjacent San Pedro Bay. To the southeast are Huntington Harbour, a neighborhood of Huntington Beach, and Sunset Beach, also part of Huntington Beach.