The Pittsburgh City-County Building is the seat of government for the City of Pittsburgh, and houses both city and Allegheny County offices. It is located in Downtown Pittsburgh at 414 Grant Street. Built from 1915 to 1917 it is the third seat of government of Pittsburgh. Today the building is occupied mostly by Pittsburgh offices with Allegheny County located in adjacent county facilities. It also contains a courtroom used for the Pittsburgh sessions of the Supreme Court of Pennsylvania.