Hiller is an unincorporated community and census-designated place in Fayette County, Pennsylvania, United States. As of the 2010 census, it had a population of 1,155, down from 1,234 at the 2000 census. It is located in Luzerne Township.
Hiller is located in western Fayette County at 40°0′33″N 79°54′16″W (40.009210, -79.904558). It is in the northeast corner of Luzerne Township, bordered to the east by Dunlap Creek, to the northeast by the borough of Brownsville, and to the northwest by the Monongahela River, which forms the Washington County line. Pennsylvania Route 43, the Mon–Fayette Expressway, passes just south of Hiller, with access from Exit 26, Telegraph Road, which becomes High Street in the center of Hiller. Via PA 43, Uniontown is 16 miles (26 km) to the southeast and downtown Pittsburgh is 41 miles (66 km) to the north.
According to the United States Census Bureau, the Hiller CDP has a total area of 1.57 square miles (4.07 km2), of which 1.52 square miles (3.94 km2) is land and 0.05 square miles (0.13 km2), or 3.08%, is water.
As of the census of 2000, there were 1,234 people, 523 households, and 357 families residing in the CDP. The population density was 813.4 people per square mile (313.5/km2). There were 567 housing units at an average density of 373.8/sq mi (144.0/km2). The racial makeup of the CDP was 91.25% White, 6.89% African American, 0.08% Native American, 0.08% Asian, and 1.70% from two or more races.