The Old Stone Wall, also known as the Galty Wall, is a historic nearly 4-kilometre (2.5 mi) stretch of expertly constructed dry stone engineering that runs across the Galtee Mountains ridge and serves as both a navigational aid and former county boundary marker between Tipperary and Limerick. This impressive stone wall, which traverses the mountain range in an out-of-the-way location, provides welcome shelter and helps keep hikers on track during adverse weather conditions, particularly valuable during the Galtee Challenge, the annual east-to-west mountain crossing completed every June that demands at least 10 hours of hiking through challenging terrain.