In its current form (post-2024 boundary changes), the seat covers the new town of Hemel Hempstead which is a significant employment centre, as well as a rural area of the Chilterns to the south-west, including the villages of Bovingdon and Flaunden.

Harpenden was transferred back to St Albans in 1974 and the constituency was temporarily abolished from 1983 to 1997 during which time it was replaced by West Hertfordshire.

Re-established for the 1997 general election from the bulk of the abolished County Constituency of West Hertfordshire (excluding Tring).

The rural Ashridge and Watling wards to the north were moved to the newly created seat of Harpenden and Berkhamsted.

The political parties had been making preparations for an election to take place from 1939 and by the end of this year, the following candidates had been selected; Craig, F. W. S. (1983).