The Allegheny County Courthouse in downtown Pittsburgh, Pennsylvania, is part of a complex (along with the old Allegheny County Jail) designed by H. H. Richardson. The buildings are considered among the finest examples of the Romanesque Revival style for which Richardson is well known. The complex is bordered by wide thoroughfares named for city founders James Ross (Ross Street), John Forbes (Forbes Avenue) and James Grant (Grant Street). The current building, completed in 1888, was designated a National Historic Landmark in 1976. Richardson later referred to it as his "great achievement". Early structures Pittsburgh's original courthouse, first occupied in 1794, was a wooden structure located on one side of Market Square. The Pennsylvania Supreme Court and from December 7, 1818, until 1841 the Western District of Pennsylvania also held court sessions at Market Square. Land for a new courthouse was purchased in April 1834. This was a tract of land on the corner of Forbes Avenue and Grant Street, on Grant's Hill. Construction took place between 1836 and 1840. This court house was built with polished gray sandstone, quarried at Coal Hill (present-day Mount Washington), opposite Water Street along the Monongahela River. The building was designed by John Chislett. The Greek Revival design included a domed cupola housing a rotunda in diameter and high. The building was completed in 1841. The building's second floor again served as the headquarters for both the Commonwealth Supreme Court Pittsburgh region and the Federal Western District, serving the latter until a new U.S. Customs House/Post Office opened on Fifth and Smithfield in 1853. Due to corrosion caused by coal smoke, the building deteriorated: the dressed surface of the facade dropped off, some of the cornices near the roof began to fall, and the building had a scaly appearance. Even in its deteriorated state, it was a handsome structure. On May 7, 1882, a fire broke out and ruined the building. Subsequently, it was demolished. The third, and present, courthouse was erected on the same spot. Current structure Following the destruction of the second courthouse, Allegheny County Commissioners decided to hold a competition to design a replacement. The winner of the competition was Boston architect Henry Hobson Richardson and construction of the buildings was begun by the Norcross Brothers, Richardson's construction firm of choice, in 1884. The cornerstone for the building was laid on October 13, 1884. The design of the main building, which Richardson