Sarn Meyllteyrn (known simply as Sarn by most) lies in the rolling countryside in the heart of the western section of the Llŷn Peninsula, on the B4413 from Llanbedrog to Aberdaron.

The village has two pubs and a petrol station/general store - and along with neighbouring Bryncroes, an annual carnival, one of the few remaining on Llŷn.

The Afon Soch flows through the village and down the valley towards Porth Neigwl (Hell's Mouth) before turning sharply into Abersoch. Sarn is situated between Mynydd Rhiw to the south and Mynydd Cefnamwlch to the northwest.