Arrowrock Dam

Historical marker location:

Boise, Idaho

( Marker is on State Highway 21 at milepost 17,, 0.2 miles south of Arrowrock Road, on the right when traveling north.)

Idaho is home to the deepest river gorge in North America, the Hells Canyon, which is more than a mile deep. It's located on the border with Oregon and is a popular destination for whitewater rafting and other outdoor activities.