Yardley borders the Delaware River and Ewing, New Jersey to its east and Lower Makefield Township to its north, west, and south.

The United States Post Office assigns many addresses in Lower Makefield Township the preferred city of "Yardley", although they are outside the borough.

He made an agreement with William Penn, before leaving England, to buy 500 acres (2.0 km2) for ten pounds.

A survey was completed in October 1682, and the area William Yardley settled was called "Prospect Farm."

He opened a ferry line which started operating in 1710 from Letchworth Avenue, the lower boundary of the village, and landed in New Jersey further downstream.

This was an important link between West Jersey and the three roads leading to Philadelphia by way of Falls, Langhorne and Newtown.

When Yardley was founded there were already small settlements at nearby Burlington, Bristol, and Falls Ferry.

During the American Civil War, Yardley was a station for the Underground Railroad, an escape route for slaves.

At Lakeside, the yellow house facing Lake Afton on N. Main Street, one brick-walled cellar room is also thought to have been a hiding place.

[12] Pennsylvania Route 32 runs through Yardley adjacent to the Delaware River, heading south to Morrisville and north to New Hope and beyond and is a scenic byway.

The Philadelphia to Bound Brook, New Jersey, two-track main line of the Philadelphia and Reading Railroad passed through and stopped at Yardley; it crossed the Delaware River on a still standing massive stone viaduct called the West Trenton Railroad Bridge.

The average wettest month is July, which corresponds with the annual peak in thunderstorm activity.

Ice storms and large snowstorms depositing ≥ 12 inches (30 cm) of snow occur once every few years, particularly during nor’easters from December through February.

[14] The spring bloom typically begins by April 7 and fall color usually peaks by November 3.