Fort Culbertson, also known as Fort Byrd and Fort Field, was located along Joshua's Run on Culbertson's (now Crump's) Bottom in present Summers County. It was built by Maj. James Robertson, who named it Fort Byrd, and his militiamen in July or August 1774. Robertson and his militiamen were from Fincastle County, a county of Virginia created in 1772 and dissolved in 1776. The construction of Fort Byrd followed orders from Col. William Preston, the surveyor of Fincastle County, who told Preston to "Construct a small stockade fort for the protection of the settlers and reception of a company [of militia]." At the time of construction, the Virginia frontier had erupted into what is known as Lord Dunmore's War, which pitted Virginia frontier settlers and militia against Indians of the Ohio Valley, particularly Shawnee and western Iroquois (often called Mingo). When Dunmore's War ended in October 1774, following the Battle of Point Pleasant and the Treaty of Camp Charlotte, Fort Culbertson, or Byrd, was under the command of Fincastle County Militia Capt. Joseph Martin.

The fort was garrisoned again by Virginia militia during the American Revolutionary War when it was again needed to protect local settlers from Indian raids. In 1777, the fort, now known as Fort Field, was under the command of Montgomery County Militia Capt. John Lucas. In April and May 1778, the area around Fort Field was invaded by "several large Parties of the Enemy [Native Americans]." These raids led to the abandonment of this region by most settlers, and as Col. William Preston stated, "we are obliged to abandon the Posts at Culbertson [commanded by Captain Joseph Cloyd] and Island Creek." Fort Field was apparently burned by Indians after its abandonment.