Blackwell House
500 Main Street
New York, NY 10044
(212) 832-4540
https://rioc.ny.gov/176/Blackwell-House
Open: Sunday 11:00am-2:00pm/3:00pm-5:00pm/Monday-Tuesday Closed/Wednesday-Saturday 11:00am-2:00pm/3:00pm-5:00pm
Free: Free
My review on TripAdvisor:

https://en.wikipedia.org/wiki/Blackwell_House
The Blackwell House on Roosevelt Island finally opened for tours after a major renovation of the house. When I had visited Roosevelt Island the last time in 2017, the house was corded off and was not open for touring. It had looked like it was falling apart from the inside out.
The home has now gone through a major renovation. The grounds outside were beautifully landscaped and gave the house a very warm and welcoming entrance to the property. In the middle of the summer, the flowers and trees were all in bloom and it was a nice view from the street. The house is conveniently located in the middle of the island, so it is not far from the tram and the subway.
I have to say that I was a little disappointed with the tour of the house what there was of it. The house had gone through a renovation but not a historic restoration, so the house is not a period piece with historic displays of furniture and art objects. It was like touring a modern home. I felt like I was walking through a 1980’s McMansion.

When you enter the front hall, there is a reproduction of a portrait of Captain Blackwell, who was a Captain in the Revolutionary War. The house was built in 1796 for James Blackwell and added to in 1804, when the family fortunes had improved after the war.
The island had been ‘patented’ to Captain John Manning by British Governor Nicolls in 1668. Before the Dutch had arrived, the island had been used by the Native Americans for hunting and fishing. The island had been inherited by the captain’s stepdaughter, Mary Manningham Blackwell and her husband, Jacob Blackwell, thus named Blackwell’s Island, upon his death. The island passed to her children, James and Jacob. The island was sold to the City of New York in 1823 (Roosevelt Island history).

All around the first floor, which is the only floor you can visit, there are all sorts of reproductions of historical maps and pictures of the island. The tour guide who had lived on the island his whole life, told me that the house had always been in disrepair and the local kids had thought it was haunted.
Now you can walk the grounds around the house and admire the beauty of the home from the outside. The only thing historical that I saw inside is when the tour guide opened the door to the cellar and showed me the stones that made up the foundation of the home. They had been quarried locally and still had the look of that time period.
The home is nice for a quick tour but do not expect much from the history side of the house.