Organization of Sixty-seven Counties of
Pennsylvania Began with Philadelphia,
March 10, 1682
The three original counties of Pennsylvania were Philadelphia, Chester and Bucks. Some authorities claim Philadelphia was the original county and the others formed soon thereafter. These authorities give the date of the erection of Philadelphia County as March 10, 1682.
Pennsylvania historians generally agree that the three were originally erected at the same time by William Penn. Philadelphia extended toward the northwest, bounded on either side by its neighboring counties, Bucks and Chester.
Bucks was called Buckingham in a letter written by William Penn to the Society of Free Traders in 1683. At that time its northern boundary was the Kittatinny Mountains, or as far as the land might be purchased from the Indians—a very indeterminate line.
Chester County included what is now Delaware County, and all the territory, except a small portion now in Philadelphia County southwest of the Schuykill, to the extreme limits of the Province.
The first county to be formed in addition to the three original counties was Lancaster, which was taken from the territory of Chester County May 10, 1729. Its boundaries then comprised “all the province lying to the northward of the Octararo Creek, and westward of a line of marked trees running from the north branch of the said Octararo Creek northeasterly to the Schuylkill.” This new county was first reduced in size August 19, 1749, when York County was cut from its territory; and secondly on January 27, 1750, when the big county of Cumberland was erected from Lancaster. The limits of Cumberland then included the whole country west to the boundary of the State, or as far as the preceding Indian purchase.
Bucks County was reduced in size when Northampton County was erected from its territory, March 11, 1752, and on the same day the County of Berks was erected from Philadelphia, Bucks and Lancaster. Thus the Province of Pennsylvania continued with the eight counties until March 9, 1771, when Bedford was formed from Cumberland, the first of the many counties taken from her territory.
Northumberland County was erected March 21, 1772, from parts of Lancaster, Cumberland, Berks, Bedford and Northampton. On account of Indian purchases now reaching to the western boundaries of the State, the limits of Northumberland reached to the western and northern boundaries of the State. Her territory was so extensive that she has been known as “The Mother of Counties,” and all or parts of thirty of the present counties of Pennsylvania have been taken from the original territory of “Old Mother Northumberland.”
February 26, 1773, was erected the County of Westmoreland, whose territory was taken from Bedford County. It then included the entire southwestern section of the State. The next county to be erected was Washington, on March 28, 1781, and its territory was taken from Westmoreland, as was the County of Fayette, formed September 26, 1783. Thus, Westmoreland was considerably reduced in size within ten years from its organization.