George Washington in Rockingham, New Jersey

When the Continental Congress retreated from Philadelphia to Princeton in 1783, George and Martha Washington took up residence 5 miles away, in rural Rockingham.

The Berrien house served as General Washington's final Revolutionary War headquarters. Here he learned the Treaty of Paris had been signed and the United States of America were an independent nation (at the time, the United States was plural “were”, the singular “was” didn’t become popular until after the Civil War). 

For eight years Washington had served his country in the American Revolution and, as one of his last official acts, wrote the Farewell Orders to the Armies of the United States while at Rockingham.

On November 5, 1783, Thomas Paine, the author of Common Sense, joined George Washington in Rockingham. Together, they conducted an experiment in the Millstone River. Poking sticks into the mud released flammable marsh gas, which they lit on fire. For the first time, there was a scientific explanation for the phenomenon known as will-o’-the-wisps.

In The Hesperus Prophecy, Washington is accused of using sorcery to help win the Revolutionary War, with reports of a mysterious light showing up before major battles. In reality, these lights are caused by Hesperus, but Washington and Paine’s experiment provides a rational explanation and satisfies his critics.

The Berrien House

Washington and Paine igniting swamp gas in the Millstone River