The small, rural town of Sunol located along Niles Canyon is well known for its historic railroad system, on which the tourist railroad Niles Canyon Railway makes an in-town stop and the Altamont Commuter Express passes en route to San Jose and the Central Valley. The large Calaveras Reservoir lies south of Sunol.
As of the census of 2000, there were 1,332 people, 483 households, and 368 families residing in the CDP. The population density was 40.6 people per square mile (15.7/km²). There were 503 housing units at an average density of 15.3/sq mi (5.9/km²). The racial makeup of the CDP was 84.46% White, 0.98% Native American, 4.80% Asian, 0.23% Pacific Islander, 4.13% from other races, and 5.41% from two or more races. 8.71% of the population were Hispanic or Latino of any race.
There were 483 households out of which 32.3% had children under the age of 18 living with them, 66.3% were married couples living together, 5.4% had a female householder with no husband present, and 23.8% were non-families. 17.2% of all households were made up of individuals and 4.8% had someone living alone who was 65 years of age or older. The average household size was 2.76 and the average family size was 3.12.
In the CDP the population was spread out with 22.7% under the age of 18, 8.2% from 18 to 24, 25.5% from 25 to 44, 33.0% from 45 to 64, and 10.7% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 106.2 males. For every 100 females age 18 and over, there were 104.4 males.
The median income for a household in the CDP was $88,353, and the median income for a family was $96,121. Males had a median income of $77,666 versus $37,102 for females. The per capita income for the CDP was $45,773. None of the families and 1.4% of the population were living below the poverty line, including no under eighteens and none of those over 64.
Probably the largest concentration of homes and population in the Sunol area consists of Kilkare Woods, which began as a private association of summer cottages.[Source:Edward G.Brooks, grandson of William Lode, Kilkare Woods maintenance manager, circa 1950's, based on Brooks' first hand knowledge]. It is located along several miles of Kilkare Road and Sinbad Creek, running generally north of Sunol proper. Kilkare Road dead ends as it begins to climb the west slope of Pleasanton Ridge. Kilkare Woods is a close-in commuter haven for southern or eastern Alameda County.
Sunol has multiple routes connecting it with Fremont, to the west, and Pleasanton-Livermore to the east. Foothill Road leads to the major crossroads of freeways 580 and 680 a few miles north, at Dublin. Niles Canyon Road is a scenic 7 mile drive west to Fremont. The major urban area of San Jose is about 15 miles to the southwest, with several driving routes available.
The Niles Canyon Railway Sunol Depot was built in 1884, and is the last surviving example of a Southern Pacific standard design known as a "One-Story Combination Depot #7." The building has been restored and is operated by the Pacific Locomotive Association.
In 1981, a Labrador retriever named Bosco was elected honorary mayor of Sunol, serving until his death in 1994. Bosco achieved a degree of international notoriety in 1990 when the Chinese newspaper The People's Daily reported on his tenure as an alleged example of the failings of the American electoral process.In 2007, Songwriter Will Stratton released a song named after the town on his first album.