History of Market Square

  • 1784: Market Square, or “The Diamond,” is part of the original plan of lots and streets laid out by George Woods and Thomas Vickroy, surveyors from Philadelphia.
  • 1794: The first Allegheny County Courthouse is constructed in the western half of The Diamond. The eastern half is filled with vendors stalls in a semi-circular market structure.
  • 1841: With the completion of a new courthouse on Grant St in 1841, the Square returned exclusively to its original intent as a public marketplace.
  • 1852: Though spared in the 1845 fire that consumed one-third of downtown, the wooden market buildings are replaced by two substantial brick buildings – each covering half of the Square and thereafter operated by the city as the Diamond Market Houses.
  • 1914: The New Diamond Market public markethouse building is constructed. The twin structures are built with openings to allow Diamond Street to pass below and, for the first time, the street (renamed Forbes Avenue) intersects with Market Street. As with its predecessor, the Diamond Market occupies all four quadrants.
  • 1961: The New Diamond Market building is demolished. Revealed once again as an open space in the downtown fabric, Market Square is refurbished as a public park and meeting place.
  • 1972: Market Square is designated by the City as its first historic district.
  • 1984: PPG Place is built. The five smaller buildings surrounding the 40-story structure are scaled back to keep with the Square’s historic area.
  • 2009: Construction begins as Market Square is rejuvenated into a European-style plaza for dining, shopping, business meetings and leisure.