St Albans is a constituency[n 1] in Hertfordshire represented in the House of Commons of the UK Parliament since 2019 by Daisy Cooper, a Liberal Democrat.

[n 2] This article also describes the eponymous parliamentary borough (1554–1852), consisting only of the city of St Albans, which elected two Members of Parliament (MPs) by the bloc vote system.

Until 1997 the seat was held by one Conservative or another save for the very early 20th century Official Opposition leadership of Henry Campbell-Bannerman and the follow-on first part of his premiership, governing in minority, and later – from 1945 – five of the six years seeing Labour's landslide Attlee ministry.

The seat swung towards the left wing on boundary changes effective in 1997, and the founding of the New Labour movement which sought public sector reform and investment with expansion based on international investor-friendly economic growth.

The three first heirs to the Earldom of Verulam have won election in the seat – the latest MP from the family was John Grimston who later became the 6th Earl (died 1973).

The Urban District of Welwyn Garden City had been formed as a separate local authority which had previously been partly in the Hitchin Division.

Moved southwards again, gaining London Colney from Hertsmere, Park Street and St Stephen's from Watford and the Three Rivers District ward of Bedmond from South West Hertfordshire.

[14] Following a local government boundary review which came into effect in May 2022,[15][16] the constituency now comprises the following wards of the City of St Albans from the 2024 general election: The seat is in Hertfordshire, England.

Neighbouring seats, clockwise from north, are: Harpenden and Berkhamsted, Welwyn Hatfield, Hertsmere, South West Hertfordshire.