Harpenden by Road

Harpenden is about 7 miles north of the M25 London Orbital Motorway and close to Junctions 9/10 off the M1.  From Junction 9 follow the signage to Redbourn, then Harpenden.  From Junction 10, take the A1081 to Harpenden.

Harpenden by Rail

Harpenden has frequent trains from central London (St Pancras International).  The journey time is about 30 minutes.
http://www.firstcapitalconnect.co.uk/Main.php?sEvent=Timetables&crs_code=HPD

Harpenden by Air

The closest international airports are Luton, Heathrow and Stansted.  From Luton, take the coach to Luton Airport Parkway train station and take the rail line direct to Harpenden.  From Heathrow, take a Piccadilly line underground train towards Cockfosters to St Pancras International and take the rail line direct to Harpenden.  From Stansted, travel by train into London and then onto St Pancras International.