🌤 Weather at Proprietary House by season
| Spring | Summer | Fall | Winter |
|---|---|---|---|
| 31–72 °F | 60–86 °F | 35–78 °F | 23–45 °F |
Each range runs from the coldest monthly average low to the warmest monthly average high in that season (1991-2020 climate normals), measured at New Brunswick 3 SE, 8 mi away, elevation 111 ft. Conditions at the park can differ from the station, especially where elevation differs — check a forecast before you go.
New Jersey’s Only Royal Governor’s Mansion — Last Surviving Original Royal Governor’s Residence in the 13 Colonies, William Franklin’s Home 1774-1776, Benjamin Franklin Family Drama, Revolutionary War Headquarters, National Register of Historic Places, Perth Amboy Middlesex County New Jersey
Proprietary House is a state historic site in Perth Amboy, Middlesex County, New Jersey — the only remaining original royal governor’s mansion in the original thirteen colonies. Completed in 1764, the house served as the official residence of William Franklin, son of Benjamin Franklin and the last Royal Governor of New Jersey, from 1774 until his arrest in 1776. The site features museum exhibits interpreting the dramatic family conflict between Benjamin and William Franklin, Revolutionary War history, colonial and Georgian architecture, guided tours, and listing on both the National and New Jersey Registers of Historic Places.
The Franklin Family Conflict
Proprietary House was the setting for one of the Revolution’s most painful personal dramas. In 1775, Benjamin Franklin visited his son William here in a last attempt to persuade him to support American independence. William refused, remaining loyal to the British Crown — a decision that permanently destroyed their relationship. In 1776, the Continental Congress ordered William Franklin placed under house arrest at Proprietary House. He was removed, tried for treason, and imprisoned, eventually dying in exile in England.
Military Headquarters
During the Revolution, the mansion served as headquarters for both sides — American General Hugh Mercer and British General Sir William Howe both used the house at different times. After the war, the building suffered fire damage, vandalism, and decades of neglect. It served as a hotel (the Brighton House), a boarding house, and a retirement home before the State of New Jersey acquired it.
Visitor Information
Today, Proprietary House is owned by the State of New Jersey and operated by the nonprofit Proprietary House Association. The museum offers guided tours interpreting the colonial governor’s lifestyle, the Franklin family conflict, and the Revolutionary War. Listed on both National and New Jersey Registers.
Frequently Asked Questions
Who was William Franklin?
William Franklin was Benjamin Franklin’s son and the last Royal Governor of New Jersey. He remained loyal to Britain and was arrested in 1776.
Can I visit?
Yes, the house operates as a museum with guided tours. Contact the Proprietary House Association for current hours.
Wildlife & Nature
Proprietary House — in Perth Amboy — is the only remaining royal governor’s mansion in the US (built 1764). William Franklin (Benjamin Franklin’s son and last Royal Governor of New Jersey) lived here. Songbirds inhabit the grounds.
Nearby Attractions
Perth Amboy — adjacent — has Raritan Bay views. Keansburg Amusement Park — 10 miles north. New Brunswick — 15 miles west.
More parks nearby: Cheesequake State Park is a short drive away, while Edison Memorial Tower lies a short drive away.
🐾 Dogs & Pets at Proprietary House
- Pets allowed? statewide rule
- Pets are allowed in NJ state parks and forests on leash but are prohibited from buildings, swimming beaches and non-designated campsites.
- Leash rule statewide rule
- Leash 6 feet or less, with the pet under physical control at all times.
- Beaches & swim areas statewide rule
- Pets are prohibited from swimming beaches and swimming waters statewide.
- Cabins & lodging statewide rule
- Pets are prohibited from cabins/lodging; the Pet Friendly Camping Program designates campsites at 13 areas (e.g. Round Valley all sites, Allaire 1-8, Bass River 1-85, Stokes 101-137) for up to two dogs or cats per permit.
- Pet fees statewide rule
- $5.00 per night additional charge for a pet-friendly campsite; no day-use pet fee.
- Statewide exceptions statewide rule
- Pet Friendly Camping requires current rabies vaccination with written proof at check-in; caged birds/reptiles only allowed inside RVs.
Are dogs allowed at Proprietary House?
Pets are allowed in NJ state parks and forests on leash but are prohibited from buildings, swimming beaches and non-designated campsites. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via dep.nj.gov. More: New Jersey state parks guide · Dog rules in all 50 states compared
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