THE lands within the present limits of the county of York were a part of Chester county from the commencement of the provincial government until the 19th of May, 1729, when they became part of a then newly erected county called Lancaster. As at that time there were but few inhabitants in what is now York county, little or no inconvenience was experienced from being at a distance from the courts of justice or from the public offices. But when the population had become more dense, and wealth had increased, it became the subject of no small complaint among the inhabitants of these parts, that they were obliged to cross the Susquehanna, and visit the borough of Lancaster, or else remain without the means of defending their rights or of redressing their grievances. At last they acquainted the governor and assembly with the great hardships to which they were subjected. They represented how difficult it was to secure themselves against thefts and abuses, frequently committed amongst them by idle and dissolute persons who resorted to the remote parts of the province, and, by reason of the great distance from the court or prison, frequently found means of making their escape." In compliance with the earnest petitions of the inhabitants, and to remedy the above mentioned inconveniences, the governor with the general assembly on the 19th of August 1749, made a division of Lancaster county, the western part of which they erected into the county of York. York was the first county west of the Susquehanna.
York county was, when first erected, bounded on the North and West by a line running from the river Susquehanna along the ridge of the South Mountain, until it intersected the Maryland line; it was bounded on the South by the Maryland line, and on the East by the Susquehanna. In the year 1750 Cumberland county was erected; and the boundary line between that and York county was declared to be the creek called the Yellow Breeches, from its mouth where it empties into the Susquehanna, up the several courses of it to the mouth of a run of water called Dogwood run, and thence one continued straight line to the ridge of the South Mountain, and thence along the ridge of the South Mountain until it intersects the Maryland line, Such continued to be the boundaries of York for about fifty years, when at last our county was destined to undergo a division.
The controversy between the inhabitants of the western and those of the eastern parts of the county concerning a division, commenced early, and was continued with warmth. Many essays were written, meetings held and petitions presented. The disputes however were at last settled, on the 22d of January 1800, when the western part of York was erected into a new county, thenceforth called Adams. That tract of land which was taken from the county of York, to be erected into a new county, is contained within the following lines, as made at the time, viz: "Beginning in the line of Cumberland county where the road from Carlisle to Baltimore leads through Trent's Gap; thence along the said road to Binder's; thence a straight line to Conewago creek opposite to the mouth of Abbot's run; thence along the line of Berwick and Paradise townships, until it strikes the line of Manhein, township; thence along the line of Manheim and Berwick westwardly, until it strikes the road leading from Oxford to Hanovertown; and from thence a due south course until it strikes the Maryland line; thence along the Maryland line to the line of Franklin county; thence along the line of Franklin and Cumberland counties to the place of beginning." The governor on the 2d of October 1800, appointed three commissioners to run and mark the dividing line between the two counties; the commissioners were Jacob Spangler, deputy surveyor of York county, Samuel Sloan, deputy surveyor of Adams county, and Mr. William Waugh.
The following townships were laid out and erected while York was a part of Lancaster county, that is before the year 1749, Hellam, Chanceford, Fawn, Shrewsbury, Codorus, Manchester, Newberry, Dover, Warrington, Monahan, Paradise, Manheim, Heidelberg, Huntingdon, Reading, Tyrone, Strabane, Menallen, Cumberland, Hamilton's Ban, Mount-joy, Germany, Mount-pleasant, and Berwick; a part of which townships are now within the limits of Adams county.
Those erected since 1749, have been York in 1753, Windsor in 1759, Hopewell in 1768, West Manchester in 1800, Washington in 1803, Fairview in 1803, Lower Chanceford in 1807, Franklin in 1809, Peachbottom in 1817, Conewago in 1818, Springgarden in 1822, Carroll in 1831.
Source: Page(s) 17-19, History of York County From its Erection to the Present Time; [1729-1834]; New Edition; With Additions, Edited by A. Monroe Aujrand, Jr.