The O'Shannassy Lodge is of regional significance due to its historical associations with the construction of the O'Shannassy scheme, the Melbourne and Metropolitan Board of Works' first major water project. (Tout-Smith 1992: 189) It is also significant for its role as a place of accommodation, having continuously housed many Australians and visitors, from O'Shannassy scheme construction workers to the Queen.

The O'Shannassy Lodge stands approximately 3 kilometres southwest of the reservoir and control weir complex, and just below an aqueduct that diverts the natural course of the O'Shannassy River towards the Silvan dam. (Tout-Smith 1992: 186)

The complex, used as a guesthouse, consists of a main office and accommodation building, a conference room, and a garage. The construction materials appear to have been predominantly local timbers. Mountain ash, cut roughly with an adze, cover some external walls. The garden is around 2 hectares and features some magnificent rhododendrons, redwoods, sycamores and beeches, and a tennis court and small golf course. (Tout-Smith 1992: 185-188)

Physical Conditions: Good

Integrity: Intact