The constituency, which crosses the boundary between the counties of Devon and Somerset, is defined as composing the following as they existed on 1 December 2020:
The District of Mid Devon wards of: Canonsleigh; Castle; Clare and Shuttern; Cranmore; Halberton; Lower Culm; Lowman; Upper Culm; Westexe.
The District of Somerset West and Taunton wards of: Alcombe; Cotford St. Luke & Oake; Dulverton & District; Exmoor; Milverton & District; Minehead Central; Minehead North; Old Cleeve & District; Periton & Woodcombe; Porlock & District; Quantock Vale; South Quantock; Watchet & Williton; Wiveliscombe & District.[5]
With effect from 1 April 2023, the District of Somerset West and Taunton was abolished and absorbed into the new unitary authority of Somerset.[6] In addition, a local government boundary review was carried out in Mid Devon which came into effect in May 2023.[7][8] The constituency therefore now comprises the following from the 2024 general election:
The District of Mid Devon wards of: Canonsleigh; Clare and Shuttern; Halberton (nearly all); Lower Culm (majority); Tiverton Castle; Tiverton Cranmore; Tiverton Lowman; Tiverton Westexe; Upper Culm.
The Somerset electoral divisions of: Dulverton and Exmoor; Dunster; Lydeard (majority); Minehead; Upper Tone (most); Watchet and Stogursey.[9]