York County, ME
History
York County was Maine’s first county, established November 20, 1652, by the Massachusetts act that also incorporated the town of Kittery. The county included all of the land claimed by Massachusetts beyond the Piscataqua River, which now defines the southern boundary of Maine with New Hampshire.In 1674, the jurisdiction of Massachusetts was extended to Muscongus Bay, near Pemaquid Point in the current town of Bristol. By 1760 its eastern boundary by identified as the St. Croix River, now the border of Washington County with New Brunswick, Canada.
On June 21, 1760, York was divided by adding two new counties within it eastern area: Cumberland and Lincoln. York County now consists of the following: the cities of Biddeford and Saco; and the towns of Action, Alfred, Arundel, Berwick, Buxton, Cornish, Dayton, Eliot, Hollis, Kennebunk, Kennebunkport, Kittery, Lebanon, Limerick, Limington, Lyman, Newfield, North Berwick, Ogunquit, Old Orchard Beach, Parsonsfield, Sanford, Shapleigh, South Berwick, Waterboro, Wells, and York.
Source: http://maineanencyclopedia.com/york-county/