Craig y Llyn is a mountain situated in Rhigos on the west side of the upper Cynon Valley in South Wales; it is the highest point in the traditional county of Glamorgan and the highest in the South Wales Valleys. It is named from the cliffs of its steep northern escarpment which overlook Llyn Fawr.

Craig y Llyn is situated in Rhigos, which lies in the Cynon Valley in the Rhondda Cynon Taff, Wales.

The hill is covered by forestry, except for the steep north and northeast faces, and is crowned with a trig point. Several footpaths cross near the summit of the hill, including the Coed Morgannwg Way, and the county boundary between Neath Port Talbot and Rhondda Cynon Taff passes 200 m to the east of the summit. The highest point in Rhondda Cynon Taff, Craig y Llyn, is commonly known as the Rhigos Mountain after the village of Rhigos located on the northern side of the mountain in the Cynon Valley.

The river Llynfell emerging from a cave at the base of the cliffs at Dan-yr-Ogof farm has always been known.
In 1912 Tommy and Jeff Morgan had the courage to explore the cave. They used only candles to light their way and arrows in the sand to find their way back.
They discovered a wonderland of stalactites and stalagmites, but they were prevented from penetrating far into the mountain by a lake.
Undeterred they returned, this time with coracles. A coracle is a traditional one man fishing boat found on the rivers of West Wales.
They crossed not one lake but four. They discovered more magnificent passages and chambers, but again the way on was denied them. This time it was a tight crawl.
This crawl was not passed until 1963 when Eileen Davies, a local girl and member of the South Wales Caving Club struggled through it.
She and others have now found over 10 miles of unique cave. Cavers believe that this is the tip of the iceberg and that there is still much to discover.
The journey through Dan-yr-Ogof is an experience you will never forget.

Glyncornel Angling Association, is home to one of the finest trout fisheries in South Wales. Stocked regularly with both Brown and Rainbow Trout, the lake has more to offer than your average catch and release small water.
The Lake is open to fly fishing only, from the 20th of March to the 17th of October.
Members are entitled to fish a maximum of 3 days per week, with no time limit on the day they fish, and have a bag limit of 2 rainbow trout per day.
You may pick and choose the 2 rainbows you will kill, or return all the rainbows caught to the lake. (as many members do not kill any fish, the choice is yours on the day)
 All Brown Trout caught are strictly on a catch and release basis only and must be returned. The lake is regularly stocked with fish 3 lbs.+ with the fishery record standing at 15 lbs. 10 ozs. for a Rainbow Trout and 15 lbs. 8 ozs. for a Brown Trout. There are many fish stocked within the range from 3 lbs up to the record as shown throughout the year.