1918–1950: The Municipal Borough of Workington, the Urban Districts of Arlecdon and Frizington, Aspatria, Harrington, and Maryport, and parts of the Rural Districts of Cockermouth, Whitehaven, and Wigton.
1950–1983: The Municipal Borough of Workington, the Urban Districts of Cockermouth, Keswick, and Maryport, and the Rural District of Cockermouth.
1983–1997: The District of Allerdale wards of All Saints, Binsey, Broughton, Castle, Clifton, Crummock, Dalton, Dearham, Derwent Valley, Ellen, Ellenborough, Ewanrigg, Flimby, Harrington, Keswick, Moorclose, Netherhall, Northside, St Bridget's, St John's, St Michael's, Salterbeck, Seaton Moor, Stainburn, and Westfield.
1997–2010: All the wards of the District of Allerdale except the Marsh, Wampool, Warnell and Wigton wards.
2010–2024: The Borough of Allerdale wards of All Saints, Aspatria, Boltons, Broughton St Bridget's, Christchurch, Clifton, Ellen, Ellenborough, Ewanrigg, Flimby, Harrington, Holme, Marsh, Moorclose, Moss Bay, Netherhall, St John's, St Michael's, Seaton, Silloth, Solway, Stainburn, Wampool, Waver, and Wharrels.
This constituency underwent boundary changes between the 1945 and 1950 general elections and thus calculation of change in vote share is not meaningful.