Oceanside is a city in the San Diego County of the US state of California. It is the 3rd largest city in the country, and as of the 2000 US census, it had an estimated population of 173,303 people. Oceanside, together with Vista and Carlsbad, form the 'Tri-City Area'. Oceanside is located south of Camp Pendleton, which is the busiest military base in the United States. Dramatic growth occurred in the area during the 1970s when the population rose to 45,000 people.

Attractions in Oceanside include the Oceanside Pier, which was first built in 1888 and attracts thousands of local residents every 4th of July eve; the Mission San Luis Rey de Francia; the grounds of Mount Ecclesia; and the California Surf Museum. The city is also the home of a bungalow house that was featured in the movie 'Top Gun', which starred American actor Tom Cruise. The final competition scene from the movie 'Bring it On' was also shot in Oceanside.