Even considering the size of Grand Teton National Park and it's incredible mountain peaks, there seems to be a lack of longer day hike options available between 10 and 20 miles. The Paintbrush Canyon to Cascade Canyon Loop combines two of the most popular canyons in the park with a high elevation pass and a picturesque alpine lake. This is among the premier day hikes in Grand Teton National Park.
While this 20-mile loop can be completed in either direction, this is far and away the more popular route mostly because of the steady and gradual ascent up and through Paintbrush Canyon and the amazing views you'll be faced with as you hike down through Cascade Canyon.
Starting from the Leigh Lake parking lot is the most efficient way to begin this loop (Jenny Lake is ideal if you'll be hiking clockwise), and the first 1.5 miles tracks all the way around Leigh Lake until you reach the Paintbrush Canyon-String Lake Trail junction, where you will take a sharp right to continue up into the canyon. From there the hike is very straightforward with virtually no other trail junctions.
If you plan on backpacking the loop, you'll find plenty of signs indicating where the backcountry camping zones begin and end as well as signage directing you to each campsite. You'll pass through four different camping zones, two in each canyon: one in each of the upper and lower sections of each canyon.
Furthermore, there's a short 0.3-mile detour to Holly Lake toward the top of Paintbrush Canyon (about 5.5 miles in), where there are additional backcountry campsites that are popular among backpackers due to the scenery and proximity to Paintbrush Pass.
Continuing past Holly Lake and through Upper Paintbrush Canyon, you can finally see the highest point of the hike at Paintbrush Divide. As you begin to climb, be mindful of the views all around you, as they are the best in Paintbrush Canyon. Even in late summer, you're likely to cross a couple short snowfields, but they're relatively flat, and you should have no problem crossing them in hiking shoes/boots.
In order to finally reach Paintbrush Divide, you'll need to carefully hike up a steep rocky section on the mountain; you'll know it when you get there. Be mindful and cautious of every step, as the rocks in this section are loose and unsettled. After a quick cautious climb you'll reach Paintbrush Divide, elevation 10,700 feet above sea level.
After you soak in the views from Paintbrush Divide, continue on the trail around the ridge and down the backside of the mountain toward Lake Solitude. You'll have a rare view of both Mica Lake and Lake Solitude as you start your descent. The hike down to Lake Solitude is the rockiest part of the entire trek, but it soon gives way to packed dirt and offers the most amazing views of Cascade Canyon and Grand Teton looming over it.
Lake Solitude offers a perfect resting spot to cool down and even take a dip if you can handle the water temperature. Continue down Cascade Canyon where you'll have endless picture opportunities for the next couple of miles. You will quickly realize why so many people choose to complete the loop in this direction. The hike down Cascade Canyon is a steady downhill trek until you reach a number of steep and narrow switchbacks leading to Jenny Lake. Follow signs to the boat dock and then veer right to head clockwise around Jenny Lake back to Leigh Lake.
After an exposed hike around Jenny Lake, you'll happen upon a swimming hole in the water connecting String Lake to Jenny Lake. After over 10 hours and 20 miles of hiking, this swimming hole is only about a half-mile from the Leigh Lake parking lot and provides a perfect opportunity to cool down before wrapping up your hike.
This hike is in bear country! Be Bear Aware! Bring bear spray, a bell, and a cannister, stay loud so as to not surprise bears, and keep your head on a swivel!