The Molonglo Plain generally refers to the flood plain of the Molonglo River and specifically the one located in the Australian Capital Territory that was inundated during the mid-1960s in order to create Lake Burley Griffin. This plain was one of fours plains - the Ginninderra Plain, the Limestone Plain, and the Tuggeranong Plain (Isabella's Plain) are the others - upon which the city of Canberra is situated.
The term Molonglo Plains refers collectively to the flood plains along the entire length of the Molonglo River, including the flood plain located north-east of Queanbeyan on the Molonglo River. The upper Molonglo Plain sometimes referred to as the Hoskinstown Plain is bordered to the east by the low ridges of the Turallo Range, Forbes Creek Ridge and Thurralilly Hill before the steep rise up to the top of the Great Dividing Range.
The area is noted as the birthplace of cricketer and Australian rules football pioneer Tom Wills.