Fort Marrow, near Huttonsville in West Virginia, is a Civil War-era Union fortification and archaeological site associated with the defenses of Camp Elkwater. The surviving work is a seven-sided enclosed earthen redoubt, and nearby ground features mark a former tent or hut area visible as 10 depressions. Its significance lies not only in the preserved fort itself but also in the surrounding traces of the camp landscape, which together illuminate the military presence there during the war. In 2010, the site was listed on the National Register of Historic Places.