Oceanside, CA has a population of 173,829 and is the 144th largest city in the United States. The population density is 4,214 per sq mi which is 1713% higher than the California average and 4551% higher than the national average. The median age in Oceanside is 37 which is approximately 2% higher than the California average of 36. In Oceanside, 56% of the population over 15 years of age are married, 69% speak English and 24% speak Spanish. 49% of Oceanside residents were born in California, 29% were born out of state, 2% were born outside of the United States and 19% were foreign born.