the library is Thomas Vose. The Garrett County Historical Society and Museums include a Historical Museum, a Transportation Museum, the Grantsville Museum and the Leo Beachley Photographic Archives. Adjacent counties Fayette County, Pennsylvania (northwest) Somerset County, Pennsylvania (north) Allegany County, Maryland, (east) Grant County, West Virginia (south) Mineral County, West Virginia (southeast) Preston County, West Virginia (west) Demographics 2020 census Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race. 2010 census As of the 2010 United States Census, there were 30,097 people, 12,057 households, and 8,437 families residing in the county. The population density was . There were 18,854 housing units at an average density of . The racial makeup of the county was 97.8% white, 1.0% black or African American, 0.3% Asian, 0.1% American Indian, 0.1% from other races, and 0.7% from two or more races. Those of Hispanic or Latino origin made up 0.7% of the population. In terms of ancestry, 35.4% were German, 13.6% identified as American, 11.3% were Irish, and 11.3% were English. Of the 12,057 households, 30.0% had children under the age of 18 living with them, 56.4% were married couples living together, 9.3% had a female householder with no husband present, 30.0% were non-families, and 25.5% of all households were made up of individuals. The average household size was 2.45 and the average family size was 2.92. The median age was 42.7 years. The median income for a household in the county was $45,760 and the median income for a family was $56,545. Males had a median income of $40,035 versus $27,325 for females. The per capita income for the county was $23,888. About 8.9% of families and 12.5% of the population were below the poverty line, including 19.2% of those under age 18 and 12.1% of those aged 65 or over. 2000 census As of the census of 2000, there were 29,846 people, 11,476 households, and 8,354 families residing in the county. The population density was 18/km2 (46/sq mi). There were 16,761 housing units at an average density of 10/km2 (26/sq mi). The racial makeup of the county was 98.83% White, 0.43% Black or African American, 0.07% Native American, 0.19% Asian, 0.02% Pacific Islander, 0.09% from other races, and 0.37% from two or more races. 0.44% of the population were Hispanic