Travel Reference
In-Depth Information
As Black Butte appears in the distance, you pass a big turnout on the road's west side and
then a lovely small cascade that enters the Gallatin River. Just beyond the cascade, look to the
east side of the road (1.1 mile north of the Y.N.P. entrance sign), and you'll see Gorilla Rock,
a jutting rock formation resembling a gorilla.
A
LONG
U.S. 191
IN THE
P
ARK
Approximately 60 miles (96 km) from Bozeman, Highway 191 enters the northwestern corner
of Yellowstone, elevation about 6,700 ft (2,040 m), and continues inside the park for about 20
miles (32 km), crossing in and out of Wyoming and Montana. There are no campgrounds,
picnic areas, or restrooms along this stretch of road, but there is access to several trails into
the backcountry, both in the park and in Gallatin National Forest. This road was first built in
1910-11 and now passes through land that was added to the park in 1929.
Road Log
0.0/20.5
Yellowstone National Park boundary. Just a large sign marks the edge of the park
here; there's no entrance fee to pay until you reach the West Entrance station.
This short stretch of U.S. 191 is the only road within the park where the speed limit is 55
miles per hour rather than 45. The only park road used by large trucks, it's open year round.
Entering park territory, you are greeted by Black Butte.
The mountains northeast of the road (to your left as you enter the park) are
Crown Butte
(elevation 8,051 ft / 2,454 m) and
Lava Butte
(7,904 ft / 2,409 m). Crown Butte resembles a
crown when seen from the south. Geologists tell us that both Crown Butte and Lava Butte
(a mile or two farther along) are topped with
Huckleberry Ridge tuff,
the 2-million-year-old
welded tephra that can be seen in several localities in the park. Here the tuff overlies
shale,
a
sedimentary rock
rich in clays. Shale weathers and erodes easily, producing landslides that
sometimes encroach upon the road.
