The Hayden Valley was once filled by an arm of Yellowstone Lake.

This is why the Hayden Valley is marshy and has little encroachment of trees.

The original lake was 200 feet (60 m) higher than the present-day lake, extending northward across Hayden Valley to the base of Mount Washburn.

In 1936, bison were transplanted to historic habitats in the Firehole River and Hayden Valley.

I drove on to Hayden Valley, where you can stop the car at frequent turnouts and look out upon the plain of the Yellowstone River.

September 23, 1869 - they travel up the Yellowstone through today's Hayden Valley to the Mud Volcano area where they camp.

Soon the green walls of lodgepole pine opened out in the broad mountain plains of Hayden Valley.

Headed east again, we crossed the ochre meadows of Hayden Valley, which had survived unburned.

Hayden Valley in Yellowstone is named after him.

Hayden Valley 4.