Kilcommon is a civil parish in Erris, north County Mayo, consisting of two large peninsulas; Dún Chaocháin and Dún Chiortáin. It consists of 37 townlands, some of which are so remote that they have no inhabitants. Habitation is concentrated mainly along both sides of Sruwaddacon Bay which flows into Broadhaven Bay, in villages including Glengad, Pollathomas, Rossport, Inver and Carrowteige, and in the Glenamoy area further inland.

Erris is a barony in northwestern County Mayo in Ireland consisting of over 230,452 acres (932.61 km2), much of which is mountainous blanket bog. It has extensive sea coasts along its west and north boundaries. The main towns are Belmullet and Bangor Erris. The name Erris derives from the Irish 'Iar Ros' meaning 'western promontory'. The full name is the Iorrais Domnann, after the Fir Bolg tribe, the Fir Domnann. To its north is the wild Atlantic Ocean and the bays of Broadhaven and Sruth Fada Conn and to its west is Blacksod Bay. Its main promontories are the Doohoma Peninsula, Mullet Peninsula, Erris Head, the Dún Chiortáin and Dún Chaocháin peninsulas and Benwee Head.