The records in this series were among an assortment received by the Australian Archives from the Heritage Architect's Office in the Department of Housing and Construction [III] (CA 3553).  The material was contained in titled folders. Some folder titles and a single number system has been imposed by Australian Archives.

Titles of the folders include GPO Site survey drawings/old surveys to Martin Place; 1881 Pitt Street extension; [George Street extension 1896-1899]; 1867 basement and ground floor plans; 1927 working drawings. Architectural and structural; 1927 structural shop drawings; 1944 floor plans; 1942 building, architectural and structural; Perspectives [1942 building]; Clock tower elevations [reconstruction and restoration]. Plans dating from circa 1968 on relate to GPO redevelopment, rehabilitation, alterations and repair of the facade.

Items within the folders are arranged numerically within prefix groups. Prefixes include 'PMG' (Postmaster-General), 'N' (New South Wales), 'NA' (NSW Architectural), 'NS' (NSW Structural). The records consist of paper originals, blue carbon copies, photocopies and transparent copies of plans, sketches and diagrams of the ongoing proposed alterations, additions to and restoration of the General Post Office building, Sydney. Other formats include photographs and an oil painting.