Rickmansworth is a town in south-west Hertfordshire, England, located approximately 17 miles north-west of central London, 5 miles south-w…Rickmansworth is a town in south-west Hertfordshire, England, located approximately 17 miles north-west of central London, 5 miles south-west of Watford and inside the perimeter of the M25 motorway. The town is mainly to the north of the Grand Union Canal and the River Colne.