size was 2.89. The population was spread out, with 442 people (17.5%) under the age of 18, 244 people (9.7%) aged 18 to 24, 585 people (23.2%) aged 25 to 44, 889 people (35.2%) aged 45 to 64, and 362 people (14.4%) who were 65 years of age or older. The median age was 44.8 years. For every 100 females, there were 98.4 males. For every 100 females age 18 and over, there were 99.0 males. There were 1,120 housing units at an average density of , of which 61.5% were owner-occupied and 38.5% were occupied by renters. The homeowner vacancy rate was 1.4%; the rental vacancy rate was 3.1%. 64.6% of the population lived in owner-occupied housing units and 35.0% lived in rental housing units. History The Mexican government granted Rancho Cotate to Captain Juan Castaneda in July 1844 for his military services in the region. The grant encompassed present-day Penngrove, Cotati and Rohnert Park. Cotate Rancho is a part of Vallejo Township which encompasses the plain between Sonoma Mountain and Petaluma Creek, San Pablo Bay, with an east–west line dividing the tract from Santa Rosa Township." Rancho Cotate was sold in 1849 to Dr. Thomas S. Page of Cotati, and eventually broken up and sold off piecemeal to incoming settlers. The first European settlers in the Penngrove area were David Wharff, W.J. Hardin, and J.M. Palmer, who arrived in 1852. In October 1870, the San Francisco and North Pacific Railroad completed the first railroad from Petaluma to Santa Rosa, running through Penngrove. Culture Every summer on the Sunday closest to July 4, Penngrove celebrates the 4th of July with a parade sponsored by the Penngrove Social Firemen. On Saturday at the Penngrove Fire Station, located at the corner of Main Street and Old Redwood Highway, the Rancho Adobe Firefighters' Association sponsors a breakfast. Name The naming of Penngrove is uncertain; there are three main "histories" of the name's origin. Ruth Anderson, the famous "Bell-Lady" of Penngrove (who lived on the site of the old schoolhouse on Oak Street), recalls, "In the late 1860s, two brothers by the name of Penn came out from Pennsylvania and bought of land in this area. They planted the area with olive trees, but when the trees matured it was found that the olives were not edible. The Penn brothers tore out many of the groves, sold the land and moved away. However,