Rohnert Park, CA has a population of 41,928 and is the 977th largest city in the United States. The population density is 5,987 per sq mi which is 2476% higher than the California average and 6508% higher than the national average. The median age in Rohnert Park is 34 which is approximately 7% lower than the California average of 36. In Rohnert Park, 46% of the population over 15 years of age are married, 77% speak English and 17% speak Spanish. 66% of Rohnert Park residents were born in California, 18% were born out of state, 1% were born outside of the United States and 15% were foreign born.