Perhaps the most unknown historic house in the country. This Colonial Mansion was not only owned by two signers of the Declaration of Independence and the Constitution, Robert Morris and George Clymer, but it also served as George Washington's Headquarters, from December 8-14, 1776.
Summerseat was the site of all kinds of historic habitation. In addition to the signers mentioned above, it was the home of Adam Hoops, a similarly forgotten financier of the French and Indian War. Another owner, Thomas Barclay, would be America's first consul, being sent to France after the first fellow died. He negotiated America's first treaty, and was the first American diplomat to die in a foreign country.
However, George Washington's week at Summerseat outshined all of the other luminaries. It was at this location that the decision to invade Trenton occurred.
Prior to his arrival, Washington was run ragged across the state of New Jersey, and narrowly escaped to Morrisville ahead of the British. His original intent, as gleaned from letters, was to regroup at Philadelphia and reevaluate the revolutionary decision. However, when he and his army departed Summerseat, they headed north instead of south, and ten days later would attack the Hessians in Trenton on Christmas Eve, a routing victory that turned the tide of the American Revolution.
The building is still open, and rentable for parties. However it may take more than a night to have a world-shaking epiphany. After all, Washington's decision to attack Trenton, while likely made inside the walls of Summerseat, was not likely made on the first day of his stay.