Today the Main Line is another name for the western
suburbs of Philadelphia along Lancaster Avenue (Route 30) and
the Pennsylvania Railroad mail line, extending from the
Philadelphia city limits to about Malvern covering an area of
about 200 square miles. The principal townships comprising the
Main Line are (from east to west) Lower
Merion Township, Haverford
Whiteland Township, and Charlestown
Township. The counties covered include Chester, Delaware,
and Montgomery Counties.
In working on early Main Line
records, the challenge lies in finding out which county
holds the records you are looking for. In previous times
the county boundaries were very different.
See where they were at http://www.pagenweb.org/imagemap.html