An amalgamation of one 25? Ordnance Survey Map of Neasden and Dollis Hill (Middlesex Sheet XI.14) and parts of two more Ordnance Survey Maps, one covering the Brent Reservoir (Welsh Harp) (Middlesex Sheet XI.10) and the other showing Chalkhill House (Middlesex Sheet XI.13). [the maps seem to have been reduced in size].
Conflicting documentation claim that the blue lines marked on the map are either Ward boundaries or Drainage districts in Willesden Parish.
The maps were surveyed 1863-4, a new railway was inserted in 1870 and the map was re-zincographed and printed in 1891.
