Brindley Mountain, also spelled Brindlee Mountain, is an isolated section of the Appalachian Plateau in northern Alabama spanning much of Cullman, Morgan, and Marshall counties and extending into Winston and Lawrence counties. Built from sandstone over limestone, with a shale layer below the top, it developed the bluffs that ring the mountain and strongly shaped local road construction, including changes along Union Hill Road and U.S. Route 231. Communities on or along the mountain include Union Hill, Morgan City, and parts of Union Grove and Arab, and its highest point is in Morgan City. It also hosts several radio towers and preserves a local curiosity: a cement mixer left from a wreck on Union Hill Road’s original alignment.