Buffalo Creek is a tributary of the Monongahela River, 30.2 miles (48.6 km) long, in northern West Virginia, in the United States. Via the Monongahela and Ohio rivers, it is part of the watershed of the Mississippi River, draining an area of 125 square miles (320 km2) on the unglaciated portion of the Allegheny Plateau. The stream's entire course and drainage basin are in Marion County. According to the West Virginia Department of Environmental Protection, approximately 84% of the Buffalo Creek watershed is forested, mostly deciduous. Approximately 14% is used for pasture and agriculture.