Twelve O'clock Knob is a mountain in southwestern Roanoke County, Virginia, just south of Salem, forming part of the ridgeline with Poor Mountain and other nearby peaks along the southwestern edge of the Roanoke Valley. Local lore ties its name to enslaved people in the western Roanoke Valley, who are said to have noticed the sun standing over the mountain around noon. That association connects the mountain to everyday timekeeping and to the region’s history of labor and enslavement. It also gained brief prominence in professional cycling when its steep, winding road became a memorable challenge in the Tour DuPont time trials of 1995 and 1996.