Fitzjohn's Avenue links Hampstead with Swiss Cottage.
Before Fitzjohn's Avenue was built, Hampstead was bounded to the south by a broad belt of green meadows, known as the Shepherds' or Conduit Fields, across which ran a pathway sloping up to the southwestern corner of the village, and terminating near Church Row
. On the eastern side of these fields wass an old well or conduit, called the Shepherd's Well, the source of the River Tyburn.
In 1874–5 it was proposed by some of the inhabitants of Hampstead to purchase a portion of these grassy slopes, and to devote them to public use as a park. This plan was brought to an abrupt halt by speculative builders, by whom the greater part of the ground was bought and laid out for building purposes.
In 1888, under the Town Improvement Scheme
, the alleyways and courtyards cluttering Hampstead Village were cleared, Heath Street
was extended and Fitzjohns Avenue
created across green fields to provide better access to the West End.
At the same time that the vvenue was constructed the Tyburn River - a tiny stream running through the fields, was diverted underground along the length of Fitzjohn's Avenue.