Complex sentence: The Big South Fork region contains one of the highest concentrations of natural bridges in the eastern United States and the area is located in parts of Scott, Fentress, Pickett, and Morgan counties in Tennessee, and McCreary County in Kentucky.
Split into simpler sentences: The Big South Fork region contains one of the highest concentrations of natural bridges in the eastern United States. The area is located in parts of Scott, Fentress, Pickett, and Morgan counties in Tennessee, and McCreary County in Kentucky.