The ceremonial county of Hertfordshire has returned 12 MPs to the UK Parliament since 2024.
Hertfordshire has been represented in Parliament since 1290. The number of MPs and the parts represented have changed considerably over time. 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.
As a result of the creation of Greater London under the London Government Act 1963, which came into effect on 1 April 1965, the boundaries of the historic/administrative county were altered, with Barnet being created as a Metropolitan Borough within Greater London and the more rural area of Potters Bar being transferred from the abolished county of Middlesex. This was reflected in the following redistribution of parliamentary seats which came into effect for the February 1974 general election and effectively reduced the county's representation by 1 MP.
The table below shows the number of MPs representing Hertfordshire at each major redistribution of seats affecting the county.
<sup>1</sup> From 2024, Hitchin is a cross-county constituency, covering parts of North Hertfordshire and Central Bedfordshire.