Placentia, CA has a population of 52,168 and is the 774th largest city in the United States. The population density is 7,888 per sq mi which is 3294% higher than the California average and 8606% higher than the national average. The median age in Placentia is 38 which is approximately 4% higher than the California average of 36. In Placentia, 59% of the population over 15 years of age are married, 61% speak English and 24% speak Spanish. 57% of Placentia residents were born in California, 17% were born out of state, 1% were born outside of the United States and 25% were foreign born.