Montana Governor and First Lady's Math and Science Initiative
Beartooth Plateau
Mile Post 69 on US 212 on the south side of Red Lodge
The Beartooth Plateau contains some of the
oldest exposed rocks on Earth and provides a
unique window into the history of our planet.
About 55 million years ago, this massive block of
metamorphic basement rock pushed its way upward
nearly two miles along steep faults that extend deep into
the Earth. The exposed rock consists of coarse-grained
gray and pink granites, gneisses, and schists that formed
about 3.3 billion years ago when older sedimentary and
volcanic rocks were heated and recrystallized deep in
the Earth at extremely high temperatures. The plateau
contains the oldest exposed rocks in Montana and they
are among the oldest on Earth. The Stillwater Complex
on the plateau’s northern flank is one of the world’s
major sources of chromite, platinum, and palladium.
During the ice ages, about 100,000 years ago, the
Beartooth Plateau collected enough snow for glaciers to
form and cover most of the plateau to a depth of several
thousand feet. The spreading glaciers wore down the
plateau’s upper surface to leave the distinctively rounded
rock outcrops, along with hundreds of lakes, ponds,
and depressions. They flowed down old stream valleys,
leaving them deepened and straightened, with vertical
canyon walls and jagged peaks. The summit of the
plateau is alpine tundra.
Beartooth Plateau Road Sign
A Brief History
Although these mountains were crisscrossed by trails used by Native Americans since prehistory, it was not until the 20th century that many sought a permanent route over the mountains from Red Lodge to Yellowstone National Park. As the Red Lodge coal mines closed, Red Lodge businessmen lobbied Montana’s congressional delegation to construct a road between their community and the Park. In 1931, President Herbert Hoover signed the Park Approach Act into law, which funded the construction of scenic routes to the country’s national parks through federally-owned land. Construction of the $2.5 million project began in 1932. Some 100 workers employed by five companies blasted their way up the side of the 11,000-foot plateau. The workmen gave names to many features of the road that are still used today, including Lunch Meadow, Mae West Curve and High Lonesome Ridge. The road officially opened on June 14, 1936. Today, the road looks much as it did in 1936 and provides motorists an excellent opportunity to experience one of the few North American highways reaching such spectacular high-elevation alpine scenery.
