The population was 18,390 at the 2010 census. According to the United States Census Bureau, the city has a total area of 13.6 square miles. 5.3 square miles of it is land, and 8.3 square miles of it (60.79%) is water.
The city of Pinole has habitat areas that support the endangered species Santa Cruz Tarweed on the California coastal prairie ecosystem. A colony of this rare plant was discovered during preparation of an Environmental Impact Report for a proposed shopping center on the east side of I-80 in the late 1980s. Subsequently a plan was developed by the city to conduct replanting of this tarweed on the slopes within the right-of-way of Interstate Highway 80. Also running through it is Pinole Creek.
The name derives from “pinole”, a Native American word for a kind of flour made from the seeds of maize, chia, and various other grasses and annual herbs. An expedition under Pedro Fages was said to have run out of provisions while exploring the area, and been fed pinole by a local village, and so the Spaniards named their camp “El Pinole”.
In 1823, Ygnacio Martinez, commandant of the Presidio of San Francisco, received a land grant of Rancho El Pinole from the Mexican government. Martinez built a hacienda in Pinole Valley at the present side of Pinole Valley Park. During the 1850s, Bernardo Fernandez, a Portuguese immigrant, started a trading facility on the shores of San Pablo Bay and eventually built the historic Fernandez Mansion, which still stands today at the end of Tennent Avenue. From these early beginnings, a small but thriving community grew into the city now known as Pinole.
The settlement grew with the coming of the Southern Pacific Railroad in 1878 and the establishment of the California Powder Works in nearby Hercules. During this period, this city had an active waterfront and was a regional commercial and banking center. The first post office also opened in 1878. The City of Pinole was incorporated in 1903.
Pinole and the surrounding area grew rapidly during the post-World War II boom. With the coming of Interstate 80 in 1958, the town evolved in a suburban bedroom community within the San Francisco/Oakland commuter belt. Much of its original industry was displaced during this time, and the town became predominantly residential.
Today, the town is locally known for its “big box” shopping store district along Fitzgerald Avenue, and Pinole Vista Shopping Center, which is continuous with Richmond’s Hilltop Area. The downtown area still retains many turn-of-the-century building stock and is being preserved by the city’s development agency as a historic area.