Roan Mountain is located in southeastern Carter County, near the Tennessee-North Carolina border. The community is situated along the upper Doe River at the river's confluence with Buck Creek. The mountain with which the community shares its name, Roan Mountain, rises several miles to the south. Reaching an elevation of , the mountain is the highest point in Tennessee outside the Great Smoky Mountains. The Appalachian Trail traverses the mountain before descending and crossing U.S. Route 19E near the state line east of the CDP, and then turning westward across the crest of White Rocks Mountain, which rises immediately north of the CDP.