1885-1918: The Municipal Boroughs of Dunstable and Luton, the Sessional Divisions of Leighton Buzzard, Luton, and Woburn, and part of the Sessional Division of Ampthill.
The 1885 county constituency was created under the Redistribution of Seats Act 1885, when the former two-seat constituency of Bedfordshire was divided into two single-member seats of Biggleswade and Luton.