Powder River Pass, Wyoming (Rt. 16).

I finally left I-90 and took Rt. 16, which crosses a section of the Bighorn Mountain Range and is advertised as a scenic alternate route on the way to Yellowstone National Park. The elevation is something like 10,000-12,000 feet -- and for any lowlanders unfamiliar with that high an altitude, the effect is that you feel twice as heavy, your lungs ache from the thin air and your car doesn't perform as well.

...and did I mention how much BRIGHTER the sun is in those higher elevations? Be sure to buy a pair of mirrored sunglasses!

Rt. 16 did indeed cross through some scenic vistas. But past the Bighorn Range, the landscape once more become flat, bright, open range land; with small towns at various intervals along the way.

I headed north on Rt. 310, expecting to cross over into Montana later that evening.