Hertfordshire is the county just north of London.
The county of Hertfordshire adjoins London, so it would depend on which part of Hertfordshire to which part of London and the traffic conditions at the time.
Hertfordshire, England.
Hertfordshire South East England
Northwest London adjoins the county of Hertfordshire, so it would depend on which part of northwest London and which part of Hertfordshire.
Stevenage, Hertfordshire, England.
Bedfordshire is in the South East of England - just North of London.
Hertfordshire in England has an area of 634 square miles. The population as of 2011 was an estimated 1,119,800 residents.
You have answered your own question - Hoddesdon is in the county of Hertfordshire in southeast England just north of London.
Stevenage, Hertfordshire, England
Elstree, Hertfordshire
Near Watford in Hertfordshire, South East England
Born: Lambeth, London, England Origin: Elstree, Hertfordshire, England