The Grand Loop Road Historic District encompasses the primary road system in Yellowstone National Park. Much of the system was originally planned by Captain Hiram M. Chittenden of the US Army Corps of Engineers 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 Lake Yellowstone.