I was led to believe that Penmaenmawr was the oldest fell race in North Wales. I think it started in 1974.
I think the pen race started in 1975. I have seen a set of results dated 1977 as being the 3rd pen race . It was originally organised by a local mountaineering club who may have had a unofficial race in 1974. It is now organised by Eryri member Chris Near.