There is substantial interest in the cost-effective extraction of unreclaimed coal reserves in highwall outcrops. Without question, there exist vast quantities of highwall coal for extraction by highwall mining systems (hms). It is estimated that 18,000 miles of highwall terrain exist in appalachia. Many of the highwalls occur along contour strip mining sites. A highwall coal reserve base of 20 billion tons is estimated for an hms capable of penetrating 850 feet. Much of these reserves consist of highly desirable low-sulfur steam and metallurgical coal. These resources are left virtually intact because current mining methods are either uneconomical or unavailable. This U.S. Bureau of Mines paper presents descriptions of past, present, and future equipment for extracting highwall coal reserves. A significant number of the hms available or under development contain features considered proprietary. Although all known hms developers were contacted and given an opportunity to provide information on their respective systems, detailed information could not be obtained in all cases.