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.

The Symonston area has traditionally been denoted 'Broadacre' area by the planning authorities, meaning that it has retained a traditionally rural character with some larger institution uses, particularly by the Australian Defence Force and Geoscience Australia.

Narrabundah Ashstone Member is found in the northern corner near the motor park.

An unnamed coarse leucogranite has a small out crop east of Jerrabomberra creek.