Boulder County is a county located in the U.S. state of Colorado. As of 2000, the population is 291,288. The county seat is Boulder. As of the census2 of 2000, there were 291,288 people, 114,680 households, and 68,808 families residing in the county. The population density was 151/km² (392/mi²). There were 119,900 housing units at an average density of 62/km² (162/mi²). The racial makeup of the county was 88.54% White, 0.88% Black or African American, 0.61% Native American, 3.06% Asian, 0.06% Pacific Islander, 4.67% from other races, and 2.18% from two or more races. 10.46% of the population were Hispanic or Latino of any race.