Maen-y-groes is a hamlet in the community of Llanllwchaiarn, Ceredigion, Wales, which is 71 miles (114.3 km) from Cardiff and 187 miles (300.9 km) from London. Maen-y-groes is represented in the Senedd by Elin Jones (Plaid Cymru) and is part of the Ceredigion Preseli constituency in the House of Commons.
The name derives from the Welsh language: "the stone of the Cross".