Mona Vale, Tasmania, Victorian mansion in Ross, Tasmania

Mona Vale is a two-storey country house of the 1860s in Ross, built of stone to designs by William Archer for Robert Kermode. Locally called the Calendar House, it has 365 windows, 52 rooms, 12 chimneys and seven entrances. Completed in 1867, it was then the largest private house in Australia.

The mansion was completed in 1867 following designs by architect William Archer and stood as a testament to Victorian prosperity in Tasmania. It later received notable visitors and became registered on the Tasmanian Heritage Register for its historic importance.

Locals call Mona Vale the "Calendar House": its 365 windows, 52 rooms, 12 chimneys and seven entrances match the days, weeks, months and days of a year. The name's origin is disputed — after Castle Mona, home of the Duke of Atholl, or from Monaeoda, the Latin name for the Isle of Man.

Mona Vale stands in Ross, in Tasmania's Northern Midlands, and is reached by local roads from the town centre. The house is on the Tasmanian Heritage Register and the Register of the National Estate, listed since 1978, so visitors view it from the outside and the grounds rather than touring the rooms. Allow time to walk the property and count the seven entrances.

During World War II, the grounds were converted into a military installation used for training and as a camp for a mounted regiment. This transformation reveals how important the property's location and infrastructure became during wartime.