Longformacus is a small village located in the Lammermuir Hills. The Dye Water runs through the village, flowing east joining with the Whiteadder Water nearby. The Southern Upland Way, passes through the village, and the Sir Walter Scott Way from Moffat to Cockburnspath passes through Longformacus. Longformacus derives its name from the Gaelic Longphort Mhacais, meaning 'Macas's camp'.
The current Longformacus Parish Church dates back to around 1730 although it is though to have reused the foundations of an earlier church possibly dating back to the 1300s. Combined with this, the church hall a scattering of cottages and modern houses this is the entirety of the village.