Grand Loop Road Yellowstone
The Grand Loop Road Historic District encompasses the primary road system in Yellowstone National Park. The US Army Corps of Engineers originally planned much of the 140-mile system in the early days of the park, when it was under military administration. The Grand Loop Road provides access to the major features of the park, including the Upper, Midway and Lower geyser basins, Mammoth Hot Springs, Tower Fall, the Grand Canyon of the Yellowstone and Yellowstone Lake.
A number of other historic districts adjoin the Grand Loop in Yellowstone, including Mammoth Hot Springs, North Entrance Road, Roosevelt Lodge, Lake Fish Hatchery and Old Faithful historic districts. Grand Loop Rd. includes unsigned portions of US 20, US 89, US 191 and US 287, all of which traverse the park. Wikipedia"