Symonston (postcode: 2609) is a primarily industrial and agricultural suburb of Canberra, Australian Capital Territory, Australia. Symonston is named after Sir Josiah Symon a Legislator, Federalist and one of the Founders of the Constitution of Australia. Located in Symonston are the Periodic Detention Centre and and three caravan parks: Canberra South Motor Park, Sundown Village and Narrabundah Longstay Caravan Park. Geoscience Australia has its headquarters in Symonston, as does the Therapeutic Goods Administration.