Gilwern Hill, Monmouthshire

Gilwern Hill is a mountain summit in Monmouthshire, Wales, rising to 441 meters within the Brecon Beacons National Park. The hilltop displays distinct rock layers including the Farewell Rock and Twrch Sandstone resting above extensive Carboniferous Limestone deposits that form its base.

Limestone quarries surrounding the hill were intensively worked during the industrial development of South Wales in the 19th century. These excavations extracted stone for the region's iron and steel production, fundamentally shaping the local economy.

The summit is protected as a scientific interest site and preserves rock layers from the Carboniferous period that reveal Earth's deep history. Visitors can observe these stone formations directly on the slopes and understand how the landscape developed over millions of years.

Multiple public footpaths and a restricted byway provide access to the northern and eastern slopes, while a minor road circles the southern and western edges. Wear sturdy footwear and check conditions as weather can change quickly at the summit.

The hilltop contains a particular geological sequence where the Farewell Rock and Twrch Sandstone rest above massive limestone beds, and this specific arrangement tells the geological story of the area. This layering allows visitors to read Earth's history literally written in the stone formations.

Elevation above the sea: 441 m

GPS coordinates: 51.80727,-3.09689

Latest update: December 14, 2025 20:04