Prior to the Revolutionary War The Fort Washington area was settled by many German immigrants. One such person was Philip Engard who immigrated in 1728. Engard purchased 100 acres (40 ha) on what was to be named Susquehanna Road and Fort Washington Avenue. By the mid-18th century the area came to be known as Engardtown, and Fort Washington Avenue was originally called Engardtown Road. The house built by Philip Engard is listed as the "Engard Family Home - 1765" in the Upper Dublin Township Open Space & Environmental Resource Protection Plan - 2005, as part of the Upper Dublin Historical Properties #25.
During the Philadelphia campaign of the American Revolutionary War, George Washington and the Continental Army were encamped here after their October 4, 1777 defeat at the Battle of Germantown, and immediately prior to their march to Valley Forge. From December 5–8, 1777, the Battle of White Marsh was fought here between British and American forces. Throughout the encampment, Washington was headquartered at the Emlen House, built by Quaker George Emlen in 1745. British commander General William Howe observed the American lines from the bell tower of St. Thomas' Episcopal Church (at Bethlehem Pike and Camp Hill Road), site of the British encampment on December 5. Today, Fort Washington State Park contains the area in which the primary American defenses were situated.
On July 17, 1856, Fort Washington was the site of one of the worst train accidents in the United States when two North Pennsylvania Railroad trains collided with one another near the Sandy Run station (later renamed to Camp Hill, now the defunct Fellwick Station). The exact number of deaths is uncertain, but 59 were killed instantly and dozens more perished from their injuries. Many of the dead were children from St. Michael's Roman Catholic Church from the Kensington section of Philadelphia, who were traveling to Sheaff's Woods, a park in the Fort Washington area, for a Sunday school picnic.
On January 1, 1946, the Township of Upper Dublin was created, and in doing so, encompassed Fort Washington along with nine other communities. Parts of Fort Washington were also incorporated into Whitemarsh Township.
The primary center of business and industry in Upper Dublin Township is the Fort Washington Office Park, which occupies 536 acres (217 ha) and contains 6,000,000 square feet (560,000 m2) of building space. There are more than 65 buildings of various sizes up to 658,535 square feet (61,179.9 m2). The park contains the offices of over 100 different companies, including Honeywell, Aetna, AccuWeather, Eastern National, Genworth Financial, and a suburban campus of Temple University. The office park was also home to the corporate headquarters of CDNow, the pioneering online music retailer. It is also home to a branch of The Paul Green School of Rock Music. In recent years, the Fort Washington Office Park has experienced a vacancy rate higher than that of other commercial/industrial parks in the region, due in some part to problems with flooding.