and here is one of the highlight views of the highway: Pilot and Index Peaks. Ferdinand Hayden gave the name "Pilot Peak" referring to the leader ("pilot") of mining expeditions. Index was originally named "Dog Turd" (it look like it from the right angle) but they renamed it "Index Finger" (which it also looks like from the Cooke City angle). Come mapping time, the name "Index" was applied.
References: Hayden's 6th Report, 1873 The Yellowstone Story; Aubrey Haines