3) Hayden Valley – This valley, centrally located in Yellowstone National Park, is the first place to go to see wildlife in Yellowstone. As you drive along this beautiful, broad valley you are likely to see herds of bison, scattered elk (and the occasional herd), and the occasional grizzly bear. You are also likely to see waterfowl, including ducks, Canadian geese and pelicans, swimming in or lounging near the Yellowstone River.
There are a number or roadside turnouts along the Hayden Valley, offering views on both sides of the road. The Yellowstone river is positioned on the east side of the roadway. Several turnouts are scenic overlooks that allow panoramic views of the Valley floor below.
The Hayden Valley was once filled by an arm of Yellowstone Lake. Therefore, it contains fine-grained lake sediments that are now covered with glacial till left from the most recent glacial retreat 13,000 years ago. Because the glacial till contains many different grain sizes, including clay and a thin layer of lake sediments, water cannot percolate readily into the ground. This is why the Hayden Valley is marshy and has little encroachment of trees.