When Mrs Doherty resigned from the position of Postmistress 1867, the Postmaster General appointed James Watts to the position of postmaster with a salary of eighteen pounds per annum. At this time the first official Post Office building in Prospect was set up in the general store owned by James Watts  James remained postmaster until his death in 1898, after which members of his family ran the post office until 1945.  During the 1920s the mail was transferred between the Blacktown Post Office and Prospect Post Office each morning and evening by horse and sulky, and later by horseback. The Prospect post office continued to operate until 1972, with Mr Albert Waldron being the last postmaster.  A mail contractor who drives a van now delivers mail from Blacktown Post Office to the Prospect residents.

The former Post Office building has important links to the history of the Prospect area because of the services it provided in regard to communication and as a general store. The fact that it is the last remaining building of the original Prospect Village is of very important significance. It is believed that  James Watts built this building between 1880 and 1890 to replace a wooden building that had burnt down. James Watts continued these duties in the new building as well as running a general store on the premises The building continued to operate as a post office and general store until 1972. After the Post Office closed the building was used as a hardware store until the NSW Planning and Environment Commission resumed the property in 1976. During the 1990s partial restoration was undertaken, which resulted in the building being repainted and re-roofed with corrugated metal. A high chain-wire fence has been erected around the property perimeter.   

Physical Description: The Post Office building is a Federation Bungalow design that has not been altered a great deal from the original design. At some time the veranda floors have been changed from flagging to concrete and the side door to the shop brick infilled. The building has retained much of the original joinery and pressed metal ceilings.