The Shire of Mount Marshall covers an area of 10134 square kilometres and is situated in the North Eastern Wheatbelt region.
It is approximately 273 kilometres northeast of Perth and has borders with the Shires of Trayning, Koorda, Mukinbudin, Yalgoo, Dalwallinu, Westonia, Yilgarn, Wyalkatchem, Sandstone and Menzies. It includes the towns of Bencubbin, Beacon, Cleary, Gabbin, Welbungin, and Wialki.
The area is primarily a wheat, coarse grain, cattle and sheep farming district.