Coordinates: 51°49′03″N 0°21′09″W / 51.8175°N 0.3524°W / 51.8175; -0.3524

Harpenden is a town in Hertfordshire, England.

The town's total population is just under 30,000.

There are two civil parishes: Harpenden and Harpenden Rural.

Harpenden railway station is on a frequent and fast rail link to central London now served by First Capital Connect, having been served previously by Thameslink. Some trains stop at 'all stations' on the route, others stop at St Albans before continuing non-stop to London St Pancras International (Harpenden to St Pancras International - 25 minutes). Trains run north to Luton and on to Bedford. From London, the trains continue south to Brighton via Gatwick, Sevenoaks or Wimbledon and Sutton. The rail link therefore gives direct access to London Luton Airport (one stop north) and London Gatwick Airport (approx 1hr 10 m on a limited stops train).

In common with much of the region, Harpenden is an area of extremely high property costs. Land Registry data suggests that the average house price in Harpenden in the 1st quarter of 2006 was £500,902 (against £287,277 for St Albans District generally, and £183,598 nationally). The data also indicates that an unusually high proportion of houses in Harpenden are owner occupied (81.4%, as opposed to 69.6% in the District generally, and 66.2% nationally).