A place once enfranchised tended to continue to be required to send members to Parliament (known as burgesses or citizens for cities and barons for the Cinque Ports), even if it always had an insignificant population or decayed over the centuries.
Since then the Boundary Commission for England has more often combined review areas to create cross border constituencies.
It was not until the local government reforms, in 1965 in the London area and 1974 elsewhere in England, that many administrative boundaries diverged in a major way from those of the historic counties.
However, as the historic counties remain the focus of local patriotism it is worth continuing the lists until the present day.
Rutland has not provided the predominant part of any constituency since 1918, but all other historic counties have contained at least one seat until the present.