Claysburg is a census-designated place (CDP) along Interstate 99 and the Allegheny Front near the base of Blue Knob (Pennsylvania). As of 2010 census, it had a population of 1,625.
As of the census of 2000, there were 1,503 people, 616 households, and 442 families residing in the CDP. There were 653 housing units at an average density of 254.9/sq mi (98.5/km2). The racial makeup of the CDP was 98.54% White, 0.13% African American, 0.33% from other races, and 1.00% from two or more races. Hispanic or Latino of any race were 0.73% of the population.
There were 616 households, out of which 35.1% had children under the age of 18 living with them, 46.9% were married couples living together, 20.1% had a female householder with no husband present, and 28.2% were non-families. 25.6% of all households were made up of individuals, and 13.5% had someone living alone who was 65 years of age or older. The average household size was 2.41 and the average family size was 2.83.
In the CDP, the population was spread out, with 26.3% under the age of 18, 8.8% from 18 to 24, 27.2% from 25 to 44, 20.3% from 45 to 64, and 17.3% who were 65 years of age or older. The median age was 36 years.