Rohnert Park is a city in Sonoma County, California, United States, located approximately north of San Francisco. The population at the 2010 United States Census was 40,971. It is an early planned city, modeled directly after Levittown, New York and Levittown, Pennsylvania. Rohnert Park is the sister city of Hashimoto in Japan. Sonoma State University, part of the California State University system, is located in the city.