But the service area and the excellent Tourist Information Centre, a hundred yards further along the road towards Clackmannan, are recent additions to the historical town that lies the other side of the motorway and predates it by a good fifteen hundred years.
Until 1890 the main settlement in the area was the hamlet of Arngask, now a few hundred yards to the east of Glenfarg. In that year the North British Railway opened a line to Perth to coincide with the completion of the Forth Rail Bridge. Glenfarg Station was built to serve this upland area on the site of a farm called Damhead. The settlement that rapidly grew up around it became equally rapidly known as Glenfarg.
Glenfarg thrived as a resort with up to four hotels at its peak. Some of the village's more unexpected buildings reflect the wealth at the time: including what used to be the Arngask Library, built in 1892, and Arngask Parish Church build in 1908.
But the railway closed in 1970, part of its track then being used for the M90 motorway which now passes mere yards to the east of the edge of the village. As a result Glenfarg is at best only briefly glimpsed by passing drivers on the motorway. And even those following the B996 which runs through the village on the course of the old Great North Road can gain an unfavourable impression, with the motorway on one side and some of the village's less well cared for buildings on the other.
But while Glenfarg may have been hit hard by the closure of the railway, it still boasts two hotels. Especially impressive and imposing is the Glenfarg Hotel which continues to dominate the heart of the village as it has since it was built to serve the railway in 1890. And those who bother to stop and explore find that the village has many other pleasant surprises in store. Behind the Glenfarg Hotel is a beautiful park and bowling green, while the more westerly parts of the village, though perhaps never quite out of hearing of the M90, retain the aura of tranquility and quality that must have been such a key to attracting visitors in the railway era.
Even the presence of a coach depot in the centre of the village doesn't seem to detract from the charm of the place. Here is a village that has faced the worst that 1970s developers could throw at it without losing its essential character.