McCoy's Fort was a regional frontier defensive fort at the home of William McCoy, one mile north of present Williamsburg in Greenbrier County. Local history suggests McCoy built his two-story log house as early as 1769. It was likely fortified about 1774 during the Indian conflict known as Dunmore's War.

William McCoy was the son of pioneer settler James McCoy and was a lieutenant in the militia under Capt. Robert McClanahan. McCoy advanced to captain after McClanahan's death at the Battle of Point Pleasant in October 1774.

Records suggest that McCoy's Fort was attacked during the Revolutionary war shortly after the failed May 29, 1778, attack on Fort Donnally, about six miles south of McCoy's Fort. Militia from nearby Renick's Fort, located about six miles east of McCoy's Fort, rushed to the aid of McCoy's Fort, which was successfully defended. Local tradition holds that six Indians died in the attack on McCoy's Fort.

The American victories at Fort Donnally and McCoy's Fort not only preserved the New River-Greenbrier settlements but also contributed to the shift to a more offensive strategy toward the Indians on the part of the Virginia government. The period of peace that followed allowed increased settlement in Western Virginia and Kentucky.

As the McCoy family prospered, they built a larger house nearby and used their old fortified house for farm use. The enclosure of their original two-story log structure within a larger frame barn sometime in the middle to late 19th century helped to preserve the fort, until strong winds in 2006 and 2012 destabilized both the outer barn and historic log structure inside. In 2013 both structures were dismantled by the Williamsburg District Historical Foundation, with the support of the Simmons family, the property owners since 1903. The original logs have been carefully documented, tagged, and stored for eventual reconstruction and public interpretation nearby. McCoy's Fort was listed as an Endangered Property by the Preservation Alliance of West Virginia in 2012, and the site was used for a public archeology program in 2013.

McCoy’s Fort was part of an elaborate frontier defense system protecting Western Virginia settlements during the Indian wars of the late 18th century. The defense system included coordinated scout patrols, local militia, and numerous forts. Other nearby forts included Arbuckle’s Fort, Fort Donnally, and Fort Savannah at present Lewisburg.