Situated above Crosskeys and Risca, and topped with what is suspected to be an Iron Age fort, Twmbarlwm is one of the most distinctive hills in the area. It has far reaching views around South Wales and the Bristol Channel, so you can see why it was a good spot for a fort.
You can access Twmbarlwm from the Valleys below, either via Cwmcarn forest (plenty of parking) or Crosskeys following part of the wonderfully named Raven Walk. This is also part of the Cambrian Way, although you might not spot any signposts for this in the area.
Whichever way you approach, you will be going up some steep parts and if you tackle it from the valley floor, it is going to be a decent ascent. You can drive up some narrow lanes and park fairly near the top if you wish, which makes the walk much shorter. The roads system that make up Cwmcarn Forest Drive have all been renewed recently, so it seems as if they are planning to open it again at some point after being shut for several years now.
This is probably one of the must-see hills in Caerphilly, and it is definitely one of the more popular peaks in the area due to its good access.
Twmbarlwm has been victim of wildfires – set by humans – occasionally which damaged some of the steps up to the fort mound and scarred the top.