Long Beach is a city situated in Los Angeles County in Southern California, on the Pacific coast of the United States. As of 2010, its population was 462,257.

The city is a dominant maritime center of the United States and was recently named "Aquatic Capital of the Nation." It wields substantial influence critical to the global economy. The Port of Long Beach is the United States' second busiest container port and one of the world's largest shipping ports. The city also maintains a large oil industry with the substance being found both underground and offshore. Manufacturing sectors include those in aircraft, car parts, electronic and audiovisual equipment, and home furnishings. It is also home to headquarters for corporations including Epson America, Molina Healthcare, and SCAN Health Plan. Long Beach has grown with the development of high-technology and aerospace industries in the area.

The town grew as a seaside resort with light agricultural uses. The Pike was the most famous beachside amusement zone on the West Coast from 1902 until 1969, it offered bathers food, games and rides, such at the Dual Ferris Wheel and Cyclone Racer' roller coaster. Gradually the oil industry, Navy shipyard and facilities and port became the mainstays of the city. In the 1950s it was referred to as "Iowa by the sea," due to a large influx of people from that and other Midwestern states. Huge picnics for migrants from each state were a popular annual event in Long Beach until the 1960s.

Oil was discovered in 1921 on Signal Hill, which split off as a separate incorporated city shortly afterward. The discovery of the Long Beach Oil Field, brought in by the gusher at the Alamitos No. 1 well, made Long Beach a major oil producer; in the 1920s the field was the most productive in the world. In 1932, the even larger Wilmington Oil Field, fourth-largest in the United States, and which is mostly in Long Beach, was developed, contributing to the city's fame in the 1930s as an oil town.

Long Beach suffers from some of the worst air pollution in southern California and the United States. Heavy pollution sources at the ports include the ships themselves, which burn high-sulfur, high-soot-producing bunker fuel to maintain internal electrical power while docked, as well as heavy diesel pollution from drayage trucks at the ports, and short-haul tractor-trailer trucks ferrying cargo from the ports to inland warehousing, rail yards, and shipping centers. Long-term average levels of toxic air pollutants (and the corresponding carcinogenic risk they create) can be two to three times higher in and around Long Beach, and in downwind areas to the east, than in other parts of the Los Angeles metropolitan area, such as the Westside, San Fernando Valley, or San Gabriel Valley. The smell of burning bunker fuel, which has an odor similar to a car burning motor oil, is not uncommon in downtown Long Beach and other port-adjacent areas. Additionally, the Long Beach area is directly downwind of several of the South Bay oil refineries.

The Port of Long Beach is the second busiest seaport in the United States and the tenth busiest in the world, shipping some 66 million metric tons of cargo worth $95 billion in 2001.

The Long Beach Sea Festival is held during the summer months (June through August). It features events centered on the ocean and the beach.

Long Beach is home to some of the USA's finest water polo players, the Long Beach State 49ers baseball team, the American Basketball Associationб the Belmont Shore rugby team, the Pep flag team at Long Beach Poly (known as the "Peppers") and others.