The government offices or as more commonly known the Treasury building was a single storey building located on the corner of King William and Flinders Streets. It was designed by George Strickland Kingston and built between 1839 and 1841. It was built in freestone and in spite being a substantial building it did not display any extravagance, perhaps reflecting the economic situation of the colony at the time. Proportion and form suggest a Renaissance influence rather than the classical style customary for official government buildings of the time.

1857 saw the beginning of a major redevelopment which was to continue in several stages until 1907 which would see the original Kingston building gradually demolished and replaced with a series of elegant two and three storey regency style buildings seen in this photograph and which exist today.

The government had no use for the buildings in the 1990s and in July 2001 after extensive refurbishment work, the buildings have a new metamorphosis as a luxury hotel complex, the Medina Grand Adelaide Treasury. This refurbishment received an Award of Merit in the 2003 UNESCO Asia-Pacific Heritage Awards for Culture Heritage Conservation.

This building is listed on the Register of the National Estate and the South Australian Heritage Register.