Bucks County is located in the U.S. state of the Commonwealth of Pennsylvania and is part of the Delaware Valley area. As of the 2010 census, the population was 625,249, which makes Bucks the fourth most populous county in Pennsylvania (after Philadelphia, Allegheny, and Montgomery counties), and the 95th most populous county in the United States. The county seat is Doylestown. Bucks County is named after the English county of Buckinghamshire.
Bucks County was one of the three original counties in Pennsylvania. It was named by William Penn in 1682 after Bucks County also called Buckinghamshire in England, the county where he lived. Bucks is the abbreviation for Buckinghamshire, and both names are used interchangeably in England. Penn's home, Pennsbury Manor, is located within Bucks County.
Place names in Bucks County derived from places in Buckinghamshire include Buckingham, Chalfont (named after Chalfont St Giles), Wycombe and Solebury (spelled Soulbury in England). Buckingham was the former county town of Buckinghamshire; Buckingham, PA, (now known as Bristol, not to be confused with the present village of Buckingham, near Doylestown) was the county seat of Bucks County from 1705–1726. Chalfont St. Giles in Buckinghamshire was the parish home of William Penn's first wife, and the location of the Jordans Quaker Meeting House, where Penn is buried.
General George Washington and his troops camped in Bucks County as they prepared to cross the Delaware River to take Trenton, New Jersey, by surprise on the morning of December 26, 1776. Their successful attack on Britain's Hessian forces was a turning point in the American War of Independence. The town of Washington Crossing, Pennsylvania and Washington Crossing Historic Park were named to commemorate the event.