Letterfrack or Letterfrac (Irish: Leitir Fraic) is a small village in the Connemara area of County Galway, Ireland. It was founded by Quakers in the mid-19th century. The village is 15 km north-east of Clifden on Barnaderg Bay and lies at the head of Ballinakill harbour. Letterfrack contains the visitors centre for Connemara National Park.