Sithney is situated in the Deanery and Hundred of Kerrier. It is bounded on the North by Crowan, on the East by Wendron and Helston and the Loe Pool which separates it from Gunwalloe, on the South by the ocean, and on the West by Breage. The parish lies about three miles North West of the town of Helston. The principal villages are the Churchtown, Porthleven, St Johns, Penrose, Mellangoose, Lower Prospidnick, Dowga, Sithney Common, Sithney Green, Coverack, Crown Town Lowertown, Chyreen and Lower Tregadjack. Porthleven, which was originally part of this parish, became a separate parish in 1844.