Garth Hill (also called Garth Mountain) is a mountain located in South Wales. It can be seen near enough all over the Welsh capital city of Cardiff, and on a sunny day as far as Weston-super-Mare across the Bristol Channel in the South West of England. It lies in the Taff Vale with the village of Pentyrch on one side and looks down onto the small village of Gwaelod-y-Garth. The Garth has a number of tumuli on its top. These date from the early to middle bronze age, around 2000 BC. They are burial sites.
A book was written about "Ffynnon Garw" which was made into a film The Englishman Who Went Up a Hill But Came Down a Mountain (1995). The location of Ffynnon Garw rather implies it is The Garth; however, the story is fictional. The popular movie has resulted in a stream of visitors climbing to the summit of Garth Mountain to view the location. It is also a popular location for people seeking magic mushrooms.
But the increased number of walkers has caused concerns for conservationists who fear the real treasure of Garth Mountain could be damaged by the myth. They say the Bronze Age burial chamber has nothing to do with the mountain's classification. Now the History Society and the local community council are erecting a notice on the mountain to explain its real historical significance.
The Garth mountain has a sister mountain, the Lesser Garth. At one time both parts of the Garth were one mountain but a geological event caused their separation. The access road to Pentyrch village, Heol Goch, runs between the main and lesser Garth. There is a quarry on the Lesser Garth.