While you are exploring Perth Amboy, be sure to make your way to Kearny Avenue or you’ll miss this important piece of American history filled with political intrigue, divided loyalties, and family tragedy.  Completed in 1764, the Proprietary House has served as a stylish hotel, a private mansion, a retirement home, a boarding house, and now a museum. Yet, its most significant period is when it served as the residence of New Jersey’s Royal Governor William Franklin, the illegitimate son of Benjamin Franklin. Today, it is the only remaining official royal governor’s mansion still standing in the original thirteen colonies.  

In February 1763, William was invested as New Jersey’s royal governor on the steps of what today is Perth Amboy’s City Hall--the country’s oldest public building in continuous use. As governor, he ran lotteries to fund roads and bridges, introduced a farmers welfare program, established America’s first Indian reservation at Brotherton (near present-day Indian Mills in Burlington County), and helped to found Queen’s College (now Rutgers University). 

William Franklin and his wife, Elizabeth Downes, moved into Proprietary House in 1774. With the outbreak of hostilities between the colonies and Britain in 1775, high drama played out at the governor’s mansion when Ben Franklin visited and tried in vain to win his Loyalist son over to the cause for independence. William remained loyal to the crown and the New Jersey Assembly ordered the Governor be held under house arrest at Proprietary House in January 1776. Soon convicted of treason, he had been not only New Jersey’s last royal governor, but also the last in the colonies still trying to cling to power. 

Freed in a prisoner exchange in 1778, William fled to New York where he remained active in the Loyalist community. In 1782, he moved to England. A staunch Loyalist, William never reconciled with his father. After the Revolution, the two only met once more in 1785 to tie some loose business ends but could not heal the wounds between them. 

Today, the Proprietary House is owned by the State of New Jersey, and the museum is operated by the non-profit Proprietary House Association. The Association serves the community by hosting guided tours, lectures, ghost tours, and teas.  

Please note: The Proprietary House is currently closed until January 2026 for safety upgrades. Keep an eye on their Facebook page for upcoming events in the meantime!