Rosemont, CA has a population of 23,081 and is the 1,890th largest city in the United States. The population density is 5,278 per sq mi which is 2171% higher than the California average and 5726% higher than the national average. The median age in Rosemont is 35 which is approximately 2% lower than the California average of 36. In Rosemont, 45% of the population over 15 years of age are married, 72% speak English and 11% speak Spanish. 62% of Rosemont residents were born in California, 17% were born out of state, 2% were born outside of the United States and 19% were foreign born.