Created on May 10, 1729 from part of Chester County and named for Lancashire, England. Lancaster, the county seat, also named for its English counterpart, was laid out in 1730. It was chartered as a borough on May 1, 1742 and as a city on March 10, 1818.

     The area was rapidly settled after 1709 by a mix of peoples: Swiss Mennonites, Huguenots, Scotch-Irish, English, Welsh, and Rhineland Germans. This was the first new county since the original three of 1682. Its rich limestone soil meant farming had to prosper. Coupled with the charitable humanitarianism of its religious values there developed a tradition that the poor could find opportunity here—“the buttermilk way.” Before 1776, Lancaster was the largest inland city in Britain’s American colonies. The decade 1800–1810 was stagnant, but then new enterprises began: gristmills, limeburning, and iron. A turnpike linked Lancaster to Philadelphia in 1800, and the Columbia and Philadelphia Railroad opened in 1834. The Conestoga Slackwater Canal facilitated trade with Baltimore. In the late nineteenth century there was a manufacturing take off including: cigars, cotton and silk cloth, beer, stoves, watches and clocks, and farm tools. The county ceasedmanufacturing iron. In this century, Armstrong Cork, R.C.A., Raybestos, Sperry-Rand, and Kerr Glass Company prospered, and some of the garments industry continues. Always Pennsylvania’s most prolific agricultural county, two-thirds of Lancaster County is farmland; animal products make up over 90 percent of farm cash receipts. Only the high prices paid for Chester County’s mushrooms compete with the cash returns from Lancaster’s harvests.

     The Christiana Riots against slavery in 1851. Lancaster was the home of Congressman Thaddeus Stevens who led the movement for justice for African Americans.