The 6.5-mile trail wraps around the world-famous lake at the base of the snow-capped Teton Mountain Range in northwest Wyoming. Just a few miles south of Yellowstone National Park, no visit to the latter would not be complete without also stopping at Grand Teton.
The trail can be reached from Yellowstone by taking U.S. Hwys. 26/89/191 south. Turn onto Teton Park Road then onto South Jenny Lake Junction. Park at the Jenny Lake Visitor Center with the trail leaving from it.
Here’s a video of Jenny Lake taken along the trail:
Here's an article more fully describing the trail.
Learn about other great national park day hiking trails in my Best Sights to See at America’s National Parks guidebook.