The Middle Fork River is formed at the community of
Adolph in western
Randolph County by the confluence of the headwaters tributaries Kittle Creek and Birch Fork, each approximately in length, which rise just north of
Kumbrabow State Forest and flow northwardly. Kittle Creek rises on the western slope of
Rich Mountain, considered to be part of the westernmost ridge of the
Allegheny Mountains and the eastern boundary of the Allegheny Plateau. From Adolph, the Middle Fork River flows generally northwardly, roughly in parallel to Rich Mountain. The river's course defines part of the boundary between Randolph and
Upshur counties, and then between Upshur and
Barbour counties, before flowing into southern Barbour County, where it joins the Tygart Valley River, approximately south of
Philippi and a few miles upstream of the mouth of the
Buckhannon River. In Upshur County it collects a tributary known as the Right Fork Middle Fork River, which rises in southwestern Randolph County and flows northwardly into eastern Upshur County. According to the West Virginia Department of Environmental Protection, approximately 94% of the Middle Fork River's watershed is
forested, mostly
deciduous, and approximately 4% is used for agriculture and pasture. ==Flow rate==