Before that, George Westinghouse purchased land in the Turtle Creek Valley in 1887 and 1888 to construct a site for his Westinghouse Air Brake Company. One of the most recognizable landmarks in the area is the General Office Building, more commonly known as the “Westinghouse Castle.” It is listed on the register of National Historic Places.
The borough is named for Joanna Wilmerding (Bruce) Negley, the wife of William B. Negley, a nephew of Thomas Mellon and local landowner.
The industrial revolution and growth of the coal, steel and rail industries along with the Air Brake facility allowed Wilmerding to flourish for many years. The decline of these industries affected this Pittsburgh suburb, as it did many. Recently, efforts began to renovate the Westinghouse Castle into a boutique hotel and spa, with the hope of turning it into a destination for visitors not only from the Pittsburgh area, but around the world.