The Dey Mansion (pronounced dye), located in modern-day Wayne, Passaic County, New Jersey, United States, and originally known as Bloomsburg Manor, played an integral role in the American Revolutionary War.

In 1641 Dirck Janszen Siecken Dey, a soldier for the Dutch West India Company, of Denmark was the first of his family to settle in the colonies.

His grandson Dirck Dey, a Denmark Dutch born planter, purchased 600 acres of land in Preakness Valley, now Wayne Township.

Theunis was a political figure who served on the state council by representing Bergen County and was a member of the charter trustee at Queens college, now Rutgers University.

Fearing that the British commander Sir Henry Clinton would seek revenge, Washington moved his army once again to the Preakness Valley's Dey Mansion, and arrived on October 8, 1780.

[6] Alexander Hamilton would leave the Dey Mansion with Washington, but would travel to Albany, where he would wed Elizabeth Schuyler on December 14, 1780.

The Dey Mansion is of Georgian style architecture with English and Dutch influences, and was built on a 600-acre lot in Preakness Valley, now Wayne, New Jersey.

List of Family Owners from its Construction to Present On January 10, 1930, the Passaic County Parks Commission acquired the land, and on October 8, 1934, it was opened for visitors.

As of 1987 the Dey Mansion has been open to the public as a museum, and it is owned and operated by the County of Passaic Department of Cultural & Historic Affairs.

It serves as a meeting place and reenactment center for many historic groups such as the Hester Schuyler-Colfax Chapter, Daughters of the American Revolution.