Mullion is situated in the Meneage district, and is in the Deanery and Hundred of Kerrier. It is bounded on the North by Cury, on the East by Ruan Major and a detached part of Grade, on the South by Landewednack and the ocean, and on the West by the ocean and Gunwalloe. The hamlets and villages are the Churchtown (now just called Mullion), Predannick, Trewoon, and Weaver. The Marconi Wireless Telegraphy Station at Poldhu received the first Morse telegraph signal across the Atlantic on 12 December 1901