They were formed for a variety of reasons, often because an area was unpopulated or unsuitable for agriculture, but also around institutions and buildings or natural resources.
The names of some former extra-parochial areas such as Nowhere, Norfolk; Nomansland, Devon; and No Man's Heath, Warwickshire point to their isolation.
Early institutions such as hospitals, almshouses and leper colonies were often made to be extra-parochial, as were houses of the gentry, depopulated villages, cathedral closes, castle grounds, Oxbridge colleges, and the Inns of Court.
Later the lack of parochial administration, including policing, would cause extra-parochial places to be used for the non-conformist religious congregation and Chartism meetings.
The problems of these areas relating to the administration of poor relief were exacerbated as the extra-parochial nature of the places attracted vulnerable people such as single women who wished to give birth there in order to avoid illegitimacy law, registration costs and parish settlement of their children by birth.
Aside from the Poor Law and civil administration, the nature of extra-parochial places caused other problems, such as rents being disproportionately high.
Because of shifts in population, it had become necessary to divide, merge and otherwise alter ancient parishes and for them to diverge for ecclesiastical and civil purposes.
A local act could be used to join the extra-parochial area to a poor law union or parish if the guardians agreed.