Brush Hill was built in 1798 by Col. John Irwin, the first member of the Irwin family to settle the area. In 1818 it was bequeathed to his grandson, John Irwin Scull, son of John Scull, founder of the Pittsburgh Gazette. It was the first mansion-scale house west of the Allegheny Mountains and the center of a 300 acre plantation. It was designated a National Historic Site on Oct. 14, 1975.