The Town Hall was built in the 1880s -- on the site of an old cemetery -- from local Sydney sandstone in the grand Victorian Second Empire style, and has been described as having "lavishly ornamented composition with focal tower and fanciful roofs." It remains the only non-religious city building from the era to retain its original function and interior. The building houses the Sydney City Council Chamber, reception rooms, the Centennial Hall and offices for the Lord Mayor and elected councillors. The Centennial Hall (main hall) contains Sydney Town Hall Grand Organ, the world's largest pipe organ with tubular pneumatic action, built from 1886 to 1889 and installed in 1890 by the English firm of William Hill & Son. This organ possesses one of only two full-length 64′ organ stops in the world (the Contra-Trombone in the pedal). Before the opening of the Sydney Opera House and its Concert Hall, the Town Hall was Sydney's premier concert hall, and many notable performances took place there.
In the later years, it has been discovered that Town Hall lies on top of part of a cemetery complex. Renovations were undertaken in 2008/9 primarily to upgrade the mechanical, hydraulic, electrical and communication services within the building. The renovations, completed by Sydney builder Kell & Rigby, included removing 6,000 cubic meters of sandstone from underneath the building. The Town Hall is listed on the Register of the National Estate and is part of the important Town Hall group of heritage-listed buildings, which also includes the Queen Victoria Building, St Andrews Cathedral, the Gresham Hotel and the former Bank of New South Wales.