Island Park, Idaho

Island Park is the name given to a broad, generally flat area just to the west of Yellowstone National Park.

It represents the floor of an ancient caldera, similar to, but older than the Yellowstone caldera which is the source of most of the Yellowstone National Park geothermal features.

The Island Park caldera is bounded by Big Bend Ridge on the south, the Centennial and Henry's Lake Mountains on the north, the Madison Plateau on the east, and Thurburn Ridge on the west. Big Bend Ridge and Thurburn Ridge actually represent the eroded rims of the ancient caldera.

The distant Teton Range from Harriman State Park (the old "Railroad Ranch") in Island Park. © Ralph Maughan

Most of Island Park is public land on the Targhee National Forest, although there are substantial inholdings of private land, many of which were made into summer home areas. Substantial new sub-division is occuring in Island Park today.

Despite the heavy timber harvest in the past twenty years, the area is very popular for recreation -- fishing the famous Henry's Fork of the Snake River, camping, driving around, and, in the winter, snowmobiling.

Revised Feb. 13, 1998