Hertsmere is a constituency[n 1] in Hertfordshire, England, represented in the House of Commons since 2015 by Sir Oliver Dowden of the Conservative Party, who is a former deputy prime minister.

[n 2] Just beyond the northwestern boundary of Greater London and with fast railway links into the capital, Hertsmere is a Parliamentary constituency in the Home Counties.

A close result for second place occurred in 2010, with only 661 votes separating the Labour Party and Liberal Democrat candidates.

[14] Hertsmere consists of the major towns and villages of Bushey, Radlett, Potters Bar and Borehamwood, elevated settlements above the headwaters of the River Colne which forms much of the northern border.

Cecil Parkinson, who had entered Parliament in 1970 and had previously represented South Hertfordshire, was MP from the seat's creation until his retirement in 1992.

[16] James Clappison held the seat for five electoral terms, from 1992 until his decision to stand down from parliament at the 2015 general election.