Eastern Idaho is in Idaho. Eastern Idaho is generally thought of as an all-season outdoor mecca above all else, with ski resorts Kelly Canyon and Pebble Creek, and extreme proximity to Yellowstone, the Tetons, Jackson, and Grand Targhee in Wyoming, each of which lie near the Idaho border. The area is also renowned in the fly fishing world as well, with travelers coming from afar to fish the Snake River and its branches and tributaries. Island Park, Bear Lake, Heise Hot Springs, and Lava Hot Springs are also regional tourist hotspots.
Fremont Country provides this nice guide to some scenic drives in the area..
Idaho state government provides several scenic drive maps as well. Here is the Teton scenic drive as an example.