The Afon Ysgethin is a short river in Gwynedd, Wales. Flowing entirely within Snowdonia National Park it rises beneath the peaks of Y Llethr and Diffwys within the Rhinogs mountain range and runs in a generally ESE direction towards Cardigan Bay. Headwater streams flow into Llyn Bodlyn reservoir and a small upper lake, Llyn Dulyn. The river emerging from the reservoir dam is crossed by an historic track at Pont Scethin. This old stone arch bridge was used historically by packhorses and drovers moving between Harlech and London. A further 3km downstream it enters a narrower wooded valley and is crossed by Pont Fadog. There are two further crossings at the village of Tal-y-bont; by the A496 road and by the Cambrian Coast railway. After another 1km it enters the sea.