Fersit (Scottish Gaelic: Fearsaid Mhòr) is a hamlet close to Tulloch railway station in Lochaber, Scottish Highlands and is in the Highland council area.
The River Treig, the outlet of Loch Treig, runs past Fersit.
Fersit had a small station on the West Highland Line, known as Fersit Halt. This was a temporary structure, used during the construction of the Lochaber hydro-electric scheme, and closed in 1935. The Lochaber Narrow Gauge Railway, a railway line built for the construction of the hydro scheme, also passed by Fersit.
Fersit has a local Met Office weather station, Tulloch Bridge. Overall it is generally colder and wetter than the UK average but with cold winters and mild summers.