As of the census of 2000, there were 53,234 people, 15,885 households, and 12,898 families residing in the county. The population density was 38 people per square mile (15/km²). There were 16,499 housing units at an average density of 12 per square mile (5/km²). The racial makeup of the county was 65.17% White, 1.08% Black or African American, 1.16% Native American, 2.40% Asian, 0.19% Pacific Islander, 24.87% from other races, and 5.14% from two or more races. 47.93% of the population were Hispanic or Latino of any race. 7.6% were of German, 6.3% Irish and 5.4% Italian ancestry according to Census 2000. 62.8% spoke English and 35.3% Spanish as their first language.
There were 15,885 households out of which 46.3% had children under the age of 18 living with them, 65.7% were married couples living together, 10.5% had a female householder with no husband present, and 18.8% were non-families. 14.1% of all households were made up of individuals and 5.4% had someone living alone who was 65 years of age or older. The average household size was 3.32 and the average family size was 3.64.
In the county the population was spread out with 32.2% under the age of 18, 8.8% from 18 to 24, 31.5% from 25 to 44, 19.3% from 45 to 64, and 8.1% who were 65 years of age or older. The median age was 31 years. For every 100 females there were 102.5 males. For every 100 females age 18 and over, there were 99.6 males.
The median income for a household in the county was $57,469, and the median income for a family was $60,665. Males had a median income of $44,158 versus $29,524 for females. The per capita income for the county was $20,932. About 6.7% of families and 10.0% of the population were below the poverty line, including 11.4% of those under age 18 and 8.5% of those age 65 or over.
San Benito County Express provides fixed route service in the city of Hollister, and intercity service in the northern portion of the county. Service operates as far north as Gilroy, in Santa Clara County.
Hollister Municipal Airport is a general aviation airport located just north of Hollister.