The brook was marked on an 1877 Ordnance Survey map and the name may have originated from a farm called Dollis, previously in Hendon.

[1] The viaduct was designed by John Fowler and Walter Brydone, chief engineer for the Great Northern Railway (GNR) from 1855 to 1861.

It is not, however, the highest altitude on the Underground system, which is near Amersham (Metropolitan line) in the Chiltern Hills, at 150 metres (490 ft) above sea level.

[6] Below the viaduct can be found the Dollis Valley Greenwalk, a long-distance footpath between Moat Mount Open Space in Mill Hill and Hampstead Heath.

This is designed to link many green spaces and wildlife corridors along the way and is approximately 10 miles (16 km) long.

An examination in the late 19th century of the railway cutting between Finchley and Hendon station found a large extent of glacial beds and fossils, and these were thought to extend as far northwest as the viaduct.