Huntington Beach is a seaside city in Orange County, California, United States. The city was originally called Pacific City, but it was changed in 1903 to be named after American businessman Henry E. Huntington. The population was 198,711 as of the 2020 United States census, making it the fourth most populous city in Orange County, the most populous beach city in Orange County, and the seventh most populous city in the Los Angeles-Long Beach-Anaheim, CA Metropolitan Statistical Area. Located 35 miles (56 km) southeast of Downtown Los Angeles, it is bordered by Bolsa Chica Basin State Marine Conservation Area on the west, the Pacific Ocean on the southwest, by Seal Beach on the northwest, by Westminster on the north, by Fountain Valley on the northeast, by Costa Mesa on the east, and by Newport Beach on the southeast.

Huntington Beach has a long 9.5-mile (15.3 km) stretch of sandy beach, mild climate, conditions considered ideal for surfing, and a strong beach culture. Swells generated predominantly from the North Pacific in winter and from a combination of Southern Hemisphere storms and cyclones in the summer focus on Huntington Beach, creating consistent surf all year long, hence the nickname "Surf City".

The Tongva village of Lupukngna was located in what became Huntington Beach, with an approximate location near the Newland House Museum. Bolsa Chica was one of the areas where the Tongva would settle during the winter. The nearby village of Genga, shared with the Acjachemen, was located across the Santa Ana River in what became Newport Beach and Costa Mesa.

The main thoroughfare of Huntington Beach, Beach Boulevard, was originally a cattle route for the main industry of the Rancho. Since its time as a parcel of the enormous Spanish land grant, Huntington Beach has undergone many incarnations. Once it was known as Shell Beach, the town of Smeltzer, and then Gospel Swamp for the revival meetings that were held in the marshland where the community college Golden West College stands. Later it became known as Fairview and then Pacific City, as it developed into a tourist destination. In order to secure access to the Pacific Electric Red Car lines that used to criss-cross Los Angeles and ended in Long Beach, Pacific City ceded enormous power to railroad magnate Henry E. Huntington, and thus became a city whose name has been written into corporate sponsorship, and like much of the history of Southern California, boosterism.

The original Huntington Beach Pier was built in 1904 and was a 1,000-foot-long timber structure. Huntington Beach was incorporated on February 17, 1909, during the tenure of its first mayor, Ed Manning. Its first developer was Huntington Beach Company (formerly the West Coast Land and Water Company), a real-estate development firm owned by Henry Huntington. The Huntington Beach Company is still a major land-owner in the city, and owns most of the local mineral rights. The company is wholly owned by the Chevron Corporation.

At one time, an encyclopedia company gave away free parcels of land (with the purchase of a complete set for $126) in the Huntington Beach area. The lucky buyers got more than they had bargained for when oil was discovered in the area, and enormous development of the oil reserves followed. Though many of the old reserves are depleted, and the price of land for housing has pushed many of the rigs off the landscape, oil pumps still dot the city.

Huntington Beach was primarily agricultural in its early years with crops such as lima beans, asparagus, peppers, celery and sugar beets. Holly Sugar was a major employer with a large processing plant in the city that was later converted into an oil refinery.

The city's first high school, Huntington Beach High School, located on Main Street, was built in 1906. The school's team, the Oilers, is named after the city's original natural resource.