Badlands National Park - South Dakota. This Park consists of nearly 243,000 acres of sharply eroded buttes, pinnacles and spires blended with the largest, protected mixed grass prairie in the United States.Over 11,000 years of human history pale to the ages old Paleontological resources. It contains the world's richest Oligocene epoch fossil beds, dating 23 to 35 million years old. The badlands are stunning! We are riding across country and stopping here is a MUST!! to see it again! Gorgeous park!