The historic Yellowstone Trail cut right through Adams County, more specifically, Hettinger. The new Yellowstone Trail Marker is now located on the southeast corner of the Court House area. The Yellowstone Trail was extended from Chicago to Seattle and, by 1917, to Boston. Yellow and black signs were posted across the country. The Association promoted the opening of Yellowstone National Park to private auto travel. Click below to read more about the process of the Yellowstone Markers.