Hamilton post office is located on 57 Gray Street, Hamilton, Victoria. It was designed by C. H. E. Blackman of the colonial Public Works Department under the aegis of William Wardell, built in 1876, and occupied in 1878.
During the 1960s, the post office underwent extensive works. This included the addition of six public telephone booths. Internal alterations included refurbishment of fixtures and finishes, replacement of original counter joinery, construction of timber-framed partition walls at first floor level, refurbishment of kitchenettes and amenities. The first floor rooms at the southern end of the building were fully refurbished with acoustic treatment for telegraph exchange.
Hamilton became a first day of issue postmarker office on 11 November 1970.