Fort Schlosser was a fortification built in Western New York in the United States around 1760 by British colonial forces, in order to guard the upper entrance to the portage around Niagara Falls, north of Porter-Barton Dock or Schlosser's Landing along the shoreline with the Niagara River.

The fort was named for its first commander, Captain Joseph Schlosser of the Royal American Regiment of Foot, a practice that was common in the British Army.

Fort Schlosser was occupied by American troops at the start of the War of 1812, but was captured in 1813 and burned.

The remains is the Old Stone Chimney was moved to the former Porter Park near the intersection of Buffalo Avenue and the Robert Moses Parkway in 1957 to near a traffic circle about 1.5 miles from the original fort site.

The chimney was relocated in 2015 and is fenced off with a sign providing details on the history of the fort.