St. Francois State Park is home to a rich diversity of native flora and fauna. From beautiful carpets of bluebells during the early spring to crimson displays of maple and oak foliage in autumn, there is always something wonderful to catch the eye. Many uncommon flowers and unique landscapes are easily observable, such as Queen of the Prairie and its fen habitat. Many areas of the park are being restored to pre-settlement open woodlands, with rich stands of prairie grasses and wildflowers. Huge sycamores more than 250 years old line the banks of Big River, with open glades dotting the bluffs above.
Several interesting animal species make St. Francois State Park their home. Enrolled in the state's Watchable Wildlife program, the park offers excellent opportunities to view popular favorites, such as white-tailed deer and wild turkey. Park visitors are just as likely to see raccoons, owls, hawks and a countless variety of songbirds. The observant visitor may even catch a glimpse of a collared lizard, beaver, bobcat or coyote. Visitors of all ages will find something remarkable at every turn.