Whiteside Mountain or Sanigilâ'gĭ in Cherokee is a mountain in Jackson County, North Carolina between Cashiers, Highlands, North Carolina, and the Georgia border. Whiteside Mountain can boast the highest cliffs in Eastern North America. It also has a feature called Devil's Courthouse, not to be confused with the Devil's Courthouse 20 miles away in Transylv…Whiteside Mountain or Sanigilâ'gĭ in Cherokee is a mountain in Jackson County, North Carolina between Cashiers, Highlands, North Carolina, and the Georgia border. Whiteside Mountain can boast the highest cliffs in Eastern North America. It also has a feature called Devil's Courthouse, not to be confused with the Devil's Courthouse 20 miles away in Transylvania County, NC.