The Register Office covering the West Derby area is Liverpool.
In registration districts for BMDs and censuses, the name Liverpool is applicable only to an area bounded by the river Mersey, Boundary Road, Great Homer St. and Upper Parliament street. All the rest of Liverpool is West Derby which is the name of the ancient Hundred ,An area which covered most of SW Lancs. It is also the name of a "village" now a suburb of Liverpool.
As the population grew parishes were split into smaller units. The same happened with registration districts so that Toxteth Park etc were split from West Derby.
The West Derby Union was established in 1837 for civil registration. Not included in the West Derby Union was Liverpool to the west, and Prescot to the east.
Forming that union were the following villages or townships.West Derby; Bootle; Everton; Fazakerley; Kirkby; Kirkdale; Walton on the Hill; Aintree; Great Crosby; Little Crosby; Inch Blundell; Litherland; Lunt; Netherland; Orrell and Ford; Sephton; Thornton; Toxteth Park; Childwall; Allerton; Garston; Wavertree; and Croxteth Park.