Old Fort Johnson is the 1749 home built by William Johnson, First Baronet of New York, British Commissioner in charge of Native American Affairs for the Northern Colonies, hero of Battle of Lake George & Fort Niagara.

This historic landmark on the Mohawk River is probably the most intact original structure remaining in North America from the French & Indian War period. It was fortified for protection during the French & Indian Wars from 1755-63. Johnson convened many Native American conferences on this site as the British Superintendent of Indian Affairs for the Northern Department.

King George II made Johnson a Baronet in 1755 after his heroic victories in the Battle of Lake George & later at Fort Niagara. 
Old Fort Johnson was one of four Johnson family homes on the eve of the American Revolution. The family remained loyal to the British Crown and had to leave the Mohawk Valley by 1776.  Their properties were seized by American patriots and the contents sold at auction.

Old Fort Johnson remained in private hands until 1906 when it was opened to the public as a historic house museum by the Montgomery County Historical Society.

It has been maintained by this nonprofit organization ever since, funded largely by memberships, donations and private fund-raising efforts. Listed as a National Historic Landmark, the property receives no operating support from any federal or state government agencies.