Bucks County was one of the three original counties in Pennsylvania. It was named by William Penn in 1682 after Buckinghamshire, England, the county where he lived and from which his family originated. 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.
Bucks County was originally much larger than it is today. Northampton County was formed in 1752 from part of Bucks County, and Lehigh County was formed in 1812 from part of Northampton County.
In December 1776, 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. 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.