Old Black is a prominent high mountain on the Tennessee–North Carolina border in the Great Smoky Mountains, notable for its dark spruce-fir forest, ancient sandstone, and broad triangular form. Part of the Guyot massif, it ranks among Tennessee’s and the national park’s highest peaks. Its rocks originated from ocean sediments nearly a billion years ago and were uplifted during the Appalachian orogeny more than 200 million years ago. Arnold Guyot measured the peak in the late 1850s, though his proposed name did not replace the local one. Since 1935, the Appalachian Trail has crossed its western slope, and the mountain remains a remote hiking destination with limited summit access and expansive views nearby.