Spring is a great season to visit Theodore Roosevelt NP; you’ll beat the summer heat and glimpse the first wildflowers. But it’s also the time when the Little Missouri River isn’t so little. Before you go, call the visitor center to check on water levels, or you could start this 15-mile loop by floating instead of wading. Follow the Petrified Forest Loop Trail up Big Plateau to the Petrified Forest Plateau. Hidden in the rock layers is an ancient fossilwood forest covered in ash from extinct volcanoes. At 2.3 miles, join the Maah Daah Hey Trail. Keep right at 2.6 miles where the Petrified Forest Loop begins. Look for bison and coyotes around the prairie-dog towns, and for mule deer, pronghorn, and elk along the riverbanks. At 5.8 miles, split left from the Maah Daah Hey to enjoy more fossilwood sites. Close the loop at 12.4 miles and retrace your route back to Peaceful Valley. Get permit (free) at the South Unit Visitor Center.Hike by Hiram Rogers, author of A Trail Guide to the Maah Daah Hey Trail, Theodore Roosevelt NP, and the Dakota Prairie Grasslands.