The Parliamentary Constituency of Hitchin & Harpenden was created in 1995 as a result of the Boundary Review.
The constituency is made up of 16 local government wards across North Hertfordshire and St Albans City & District Councils:
- Cadwell.
- Chesfield.
- Harpenden East.
- Harpenden North.
- Harpenden South.
- Harpenden West.
- Hitchin Bearton.
- Hitchin Highbury.
- Hitchin Oughton.
- Hitchin Priory.
- Hitchin Walsworth.
- Hitchwood, Offa and Hoo.
- Kimpton.
- Redbourn.
- Sandridge.
- Wheathampstead.
There are major population centres in Harpenden, Hitchin, Great Ashby, Redbourn, Sandridge, Jersey Farm and Wheathampstead. Notable villages in the constituency include Pirton, Holwell, Ickleford, Offley, Lilley, Hexton, St Paul's Walden, King's Walden, St Ippolyts, Breachwood Green, Preston, Little & Great Wymondley, Langley, Kimpton, Kinsbourne Green and Whitwell.