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 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.
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 Interstate Highway 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.
As of the census of 2000, there were 19,039 people, 6,743 households, and 5,057 families residing in the city. The population density was 1,413.7/km² (3,662.3/mi²). There were 6,828 housing units at an average density of 507.0/km² (1,313.4/mi²). The racial makeup of the city was 54.39% White, 11.11% Black or African American, 0.57% Native American, 21.71% Asian, 0.37% Pacific Islander, 5.81% from other races, and 6.03% from two or more races. 13.75% of the population were Hispanic or Latino of any race.
There were 6,743 households out of which 34.8% had children under the age of 18 living with them, 56.6% were married couples living together, 13.5% had a female householder with no husband present, and 25.0% were non-families. 20.2% of all households were made up of individuals and 7.9% had someone living alone who was 65 years of age or older. The average household size was 2.79 and the average family size was 3.23.
In the city, the population was spread out with 25.0% under the age of 18, 7.8% from 18 to 24, 28.3% from 25 to 44, 26.0% from 45 to 64, and 12.9% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 92.4 males. For every 100 females age 18 and over, there were 87.6 males.
The median income for a household in the city was $62,256, and the median income for a family was $70,172. Males had a median income of $47,335 versus $38,019 for females. The per capita income for the city was $25,170. About 3.5% of families and 5.0% of the population were below the poverty line, including 5.5% of those under age 18 and 8.0% of those age 65 or over.