Oroville, CA has a population of 18,884 and is the 2,312th largest city in the United States. The population density is 1,366 per sq mi which is 488% higher than the California average and 1408% higher than the national average. The median age in Oroville is 33 which is approximately 8% lower than the California average of 36. In Oroville, 42% of the population over 15 years of age are married, 84% speak English and 6% speak Spanish. 72% of Oroville residents were born in California, 19% were born out of state, 1% were born outside of the United States and 7% were foreign born.