One of the most popular hikes in Grand Teton National Park  is this 19-mile loop trip up Cascade Canyon, over Paintbrush Divide, and down Paintbrush Canyon (or vice versa). The trip offers a little of everything: dense forests, alpine lakes, flower-covered meadows, and magnificent views of the Tetons.
It is best done in late summer, because a cornice of snow typically blocks Paintbrush Divide until the latter part of July. Most folks do it as an overnight trip, but it’s possible to do the entire loop in a single very long day if you’re in good shape and have a masochistic streak. Be sure to bring plenty of water along.
Begin at the String Lake Trailhead and head south around Jenny Lake , stopping to enjoy the views (and crowds) at Inspiration Point before heading up along Cascade Creek. The trail splits at the upper end of this canyon; turning left takes you to Hurricane Pass and the Teton Crest Trail, where you’ll discover wonderful views of the back side of Grand Teton.
Instead, turn right (north) and head up to beautiful Lake Solitude. Behind you, Teewinot, Mt. Owen, and Grand Teton are framed by the glacially carved valley walls. Above Lake Solitude, the trail climbs sharply to Paintbrush Divide and then switchbacks even more quickly down into Paintbrush Canyon. The trail eventually leads back to String Lake.
Be sure to stop at beautiful Holly Lake on the way down.