[2] It is said that the Marquis of Salisbury, who lived at Hatfield House, wanted a route to the Great West Road avoiding central London, for onward travel to the spa towns of Bath and Cheltenham where, as a sufferer of gout, he often took the waters.

With others (including the Earl of Essex, who suffered from a similar affliction, and who lived at Cassiobury House near Watford) he sponsored an act of Parliament[which?]

It ran via St Albans, Watford, Rickmansworth, Amersham, High Wycombe and Marlow, with two alternative routes south and west from there, one to Knowl Hill (on the Great West Road between Maidenhead and Reading) and the other to Reading itself via Henley-on-Thames.

[3][4][5][6] Analysis of toll receipts shows that traffic was lighter than that on the great trunk routes it interconnected.

[7] On classification by the newly formed Ministry of Transport in 1922, it formed parts of the A414 (Hatfield - St Albans), A412 (St Albans - Watford - Rickmansworth), A404 (Rickmansworth - Amersham), A416 (Amersham - High Wycombe - Marlow - Knowl Hill) and A32 (Marlow - Henley - Reading).