Karthaus is an unincorporated community in Clearfield County, Pennsylvania, United States. The community is located along Pennsylvania Route 879, east-northeast of Clearfield. Karthaus has a post office with ZIP code 16845, which opened on April 24, 1826. The community was named after Peter A. Karthaus, the proprietor of a local blast furnace.
The United States Census Bureau defined Karthaus as a census designated place (CDP) in 2023.