Lewannick is situated in the Deanery and Hundred of East. It is bounded on the North by Trewen and South Petherwin, on the East by Lezant, on the South by North Hill, and on the West by Altarnun. The parish is five miles south-west of Launceston. The main hamlet is Trelaske; this is the Trelosch of the Domesday Survey of 1086. The principal villages and hamlets besides the Churchtown are Polyphant, Trevadlock, and Tinney Hall.