Redstone Old Fort or Redstone Fort or Fort Burd was the name of a wooden fort built about 1759 by English explorers on a mound overlooking the eastern shore of the Monongahela River in what is now Fayette County, Pennsylvania near Redstone Creek. The site was located at the crossing point of the formidible east-west obstacle of the Monongahela River along the route of an Amerindian trail from the Potomac River. In 1789, historic Nemacolin Castle, trading post, and tavern was built near this crossing. The settlement around the fort also came to be called Redstone, but eventually became eponymously known as Brownsville, Pennsylvania after its farsighted developer Thomas Brown, and use of "Redstone" devolved to apply to just one of its neighborhoods.

Geopolitically, Redstone was a frequent point of embarkation to cross the Monongahela River for travelers who had crossed the Alleghenies or were heading west via the Monongahela and Ohio Rivers by boat. Its strategic importance was recognized by the indigenous Amerindians, and it was a target terminus of Braddock's Road during the French and Indian War
A third and larger group that included George Rogers Clark, had gathered at the mouth of the Little Kanawha River (the present site of Parkersburg, West Virginia), and were waiting there for the arrival of other Virginians who were expected to join them at that point before moving downriver to settle lands in Kentucky.

Redstone Old Fort is mentioned in C. M. Ewing's The Causes of that so called Whiskey Insurrection of 1794 (1930) as being the site of a July 27, 1791, meeting in "Opposition to the Whiskey Excise Tax," during the Whiskey Rebellion, the first illegal meeting of that insurrection.

In 1803 it was a mentioned in a letter from Meriwether Lewis to President Thomas Jefferson detailing his route from Harper's Ferry to Pittsburgh.