Penngrove Lodging - Penngrove Restaurants - Penngrove Activities View all listings in Penngrove Penngrove Facts Driving Time / Directions: Penngrove Weather: View Current Weather Penngrove Map: View Location On Map Penngrove Zip Code: 94951 Penngrove Elevation: 89 feet Penngrove's Local Events View all upcoming events here... Specials near Penngrove View all specials in Sonoma County... About Penngrove Located between the towns of Petaluma and Cotati, just a few miles off Highway 101, the unincorporated town of Penngrove boasts about 4,000 residents and sits in the foothills of Sonoma Mountain. Historians say it once sat in a grove of olive trees and records show that it was a well-known center for chicken and egg farming. The town was also the site of 3 major cobblestone quarries in the late 19th century and Penngrove stone was used to pave the streets of San Francisco. Today, visitors stop in Penngrove to view a number of old, historic buildings. Check out the post office, built in 1882; the Penngrove Community Church, constructed around the turn of the century; and the cool 1938 art deco firehouse. Penngrove activities should include gallery browsing as several fine artists have made their home in this small town. For outdoor fun, visit the Fairfield Osborn Preserve, part of nearby Sonoma State University, dedicated to "protecting and restoring natural communities and to fostering ecological understanding through education and research." Classes, lectures, hikes, and children's programs are available at the Preserve.