History of parliamentary constituencies and boundaries in Hertfordshire

In 1885 there were just four seats and this has increased by one at each major redistribution which came into effect for the general elections of 1918, 1945, 1950, 1955, February 1974, 1983, 1997 and 2024.

The table below shows the number of MPs representing Hertfordshire at each major redistribution of seats affecting the county.

In 1852, St Albans was disenfranchised for electoral corruption and, under the Reform Act of 1867, the representation of the Borough of Hertford was reduced to 1 MP.

The new constituency of South Hertfordshire was made up as follows: To compensate St Albans, Harpenden and Redbourn were transferred from Hemel Hempstead.

Broxbourne was formed as a Borough Constituency, primarily from southern parts of East Hertfordshire, consisting of the former Urban Districts of Cheshunt and Hoddesdon which had been combined to form the District of Broxbourne under the local government reorganisation.