St Dennis is situated in the Deanery and Hundred of Powder. It is bounded on the North by the parish of Roche, on the East by Roche and St Stephen-in-Brannel, on the South by St Stephen-in-Brannel, and on the West by St Enoder and St Columb Major. The parish lies to the North-West of St Austell and is bounded to its North-West by the River Fal. There is an area of moorland called Goss Moor to the north. The Churchtown was built up for clay workers and comprises numerous cottages. The principal villages and hamlets are Hendra, Whitebait, Treleaver, and Enniscavan.