Rib Mountain, or Rib Hill, is a striking isolated landform in central Wisconsin southwest of Wausau on the west side of the Wisconsin River. A glacially eroded monadnock formed from rock intruded about 1.5 billion years ago, it consists of quartzite with a softer syenite sheath and endures as an isolated rise after long erosion of the surrounding landscape. Nearly 4 miles long and 1,942 feet above sea level, it rises 741 feet above nearby terrain and is Wisconsin’s fourth-highest point. Now home to Rib Mountain State Park and Granite Peak Ski Area, it is both a major recreation site and an important radio and television transmission location for the Wausau area.