Butler County, Pennsylvania, was created on March 12, 1800, from a portion of Allegheny County. Like many other western Pennsylvania counties, Butler County was named for a Revolutionary War hero, General Richard Butler. The county seat, the Borough of Butler, was laid out in 1803, and on April 2, 1803, the county was formally organized for judicial purposes.
The official boundaries of Butler were defined in 1800 as follows: Beginning at a locust tree on the south side of Buffalo Creek (near Freeport), thence along the Allegheny line due west 23 miles, thence due north 23 miles, then north 35 degrees east 15 miles, then east to the Allegheny River, thence due south to the place of beginning. Thus, the shape of Butler County is a rectangle (33 miles NS by 23 miles EW) with north-western corner removed diagonally. The boundaries of Butler County, in contrast to many other Pennsylvania counties, have remained unchanged from its creation to the present.
Butler County is bordered by eight other Pennsylvania counties:
The Commonwealth of Pennsylvania considers that Indian title to all the land in Butler County (along with most of northwestern and northcentral PA) was extinguished in 1784 by what is called the Last Purchase. Prior to 1784, the northern border of the Western Pennsylvania land to which Pennsylvania claimed to enjoy clear title ran from Cherry Tree, Indiana Co. to Kittaning, Armstrong Co., and from there down the Allegheny and Ohio Rivers to the western border of the state. During the Revolutionary War, most of the Indian nations in western PA had been allied with the British, and when the British signed the Treaty of Paris in 1783, these Indians were forced to negotiate peace treaties with colonists on unfavourable terms. On October 22, 1784, the Seneca and the other 5 Iroquois nations signed the Treaty of Fort Stanwix. On January 21, 1785, the Delaware and Wyandot signed the similar Treaty of Fort McIntosh. On January 31, 1786, the Shawnee signed the similar Treaty of Fort Finney.
Even before the above treaties, the Commonwealth of Pennsylvania had begun to plan for the eventual distribution of this land to its citizens. On March 12, 1783, Pennsylvania established the Depreciation and Donation Land Districts which included all of Pennsylvania north and west of the Allegheny and Ohio Rivers. The Depreciation Land District included portions of modern Allegheny, Armstrong, Butler, Beaver, and Lawrence Counties, while the Donation Land District included part (or all) of the following counties: Armstrong, Butler, Lawrence, Mercer, Venango, Forest, Crawford, Warren, and Erie Counties. Surveys of land in these districts were begun in 1785 or 1786, and the first patents were distributed soon after. On April 8, 1785, the entire extent of the Depreciation and Donation Land Districts was annexed to Westmoreland County, and on September 24, 1788, when Allegheny County was created, these districts were transferred to Allegheny County.
The actual settlement of these areas was delayed by the resumption of hostilities between the Shawnee, Delaware, and Wyandot and the United States in 1787. On August 20, 1794, General Wayne decisively defeated these Indian nations at the Battle of Fallen Timbers in Defiance County, Ohio, and on August 3, 1795, the Treaty of Greenville brought hostilities to an end.
As the threat of attack by the Indians declined during this period, the actual settlement of land in Butler County began. On Apr 3, 1792, the Settlement Law of 1792 was passed by Pennsylvania, and this provided a major impetus to migration into the Depreciation and Donation Districts. It is thought that the first white man to settle permanently in Butler Co. was James GLOVER, who in 1792 built a cabin in Adams Township. Peter McKINNEY is also thought to have settled in Forward Township in 1792, and one of his children is said to have been born there that year. If so, this is probably the first white birth in the county. (Reports of earlier white births in Butler County usually do not hold up under serious genealogical scrutiny.) Many other early settlers arrived in the next few years, and after peace was restored in 1795, the population of the area increased rapidly. As a result of the rapid growth, it was determined that Allegheny County should be subdivided, and on Mar 12, 1800, eight new counties, including Butler County, were created. When the census was taken later that year, the population of Butler County was found to have grown to 3,916.