Oceanside is the third-largest city in San Diego County. The city has a population of about 179,681. Together with Vista and Carlsbad, it forms a tri-city area. The city is located just south of Camp Pendleton, the busiest military base in the United States. Oceanside has experienced dramatic growth since 1970, when its population was 45,000. Much of the city's area was developed into single-family home tracts during the 1970s and 1980s. Since the 1990s, increased commercial and industrial development have diversified Oceanside's economic base.