Machen can be found east of Caerphilly in South Wales. It sits upon the A468 road which runs from Caerphilly in the west to Newport in the east. The river Rhymney also passes through the village, flowing onwards through Caerphilly and Bedwas before meeting the Severn estuary at Cardiff Bay.

There are many walks criss-crossing the hills and valleys and the Rhymney Valley Ridgeway Walk and the Rhymney River Circular Walk meet up at Machen where they cross the River Rhymney.

Mynydd Machen (Machen Mountain) provides a spectacular backdrop for the village. Visitors to the area are able to climb to the top of the mountain, where a group of boulders known as 'The Devil's Apron Strings' can be found. The boulders hold their own tales about South Wales. It is said that Saint Peter was visiting Wales, when suddenly he saw the Devil before him. Slowly, he began to pick up several boulders and placed them in his apron. He then began running from the Devil, who chased after him on the mountain. After some time the Devil ran out of breath and Saint Peter began throwing the boulders at him in order to get him away.