Fort Schlosser, Fort site in Niagara Falls, New York, United States

Fort Schlosser was a British stockade fort built around 1760 on the Niagara River in what is now Niagara Falls, New York, guarding the upper end of the portage around Niagara Falls. Inside the wooden palisade stood two storehouses and separate quarters for officers and soldiers, with four cannons for defence. The Old Stone Chimney from Fort Little Niagara was incorporated into the fort.

Built around 1760 by British colonial forces, Fort Schlosser replaced the French Fort Petite Niagara, which the retreating French burned before the 1759 Siege of Fort Niagara. The Old Stone Chimney from Fort Little Niagara was incorporated into the new fort. American troops occupied it at the start of the War of 1812, but it was captured in 1813 and burned.

The fort was named after its first commander, Captain Joseph Schlosser of the Royal American Regiment of Foot, a common British Army practice. The Old Stone Chimney from Fort Little Niagara was built into the fort; it was moved to Porter Park in 1957 and relocated again in 2015, now fenced off with a sign on the fort's history.

The fort site lies in present-day Niagara Falls, New York, near the New York Power Authority water intakes off the Robert Moses Parkway. The surviving Old Stone Chimney was moved in 1957 to former Porter Park near Buffalo Avenue and the Robert Moses Parkway, then relocated again in 2015; it now stands fenced off with an information sign about the fort's history.

The fort's only surviving structure, the Old Stone Chimney, came from the earlier French Fort Little Niagara and was built into Fort Schlosser. It was moved in 1957 to Porter Park near Buffalo Avenue and the Robert Moses Parkway, about 1.5 miles from the fort site, then relocated again in 2015 and now stands fenced off with an information sign.