Douglas County is a suburban county located in the southern portion of the Denver-Aurora metropolitan area of the U.S. state of Colorado. As of 2000, the population is 175,766. Douglas County is one of the fastest growing areas in Colorado. The county seat is Castle RockAs of the census2 of 2000, there were 175,766 people, 60,924 households, and 49,835 families residing in the county. The population density was 81/km² (209/mi²). There were 63,333 housing units at an average density of 29/km² (75/mi²). The racial makeup of the county was 92.77% White, 0.95% Black or African American, 0.41% Native American, 2.51% Asian, 0.06% Pacific Islander, 1.43% from other races, and 1.88% from two or more races. 5.06% of the population were Hispanic or Latino of any race.