Until the mid-19th century, Big Thicket was a dense and mysterious forest where Civil War draft dodgers hid out. Today the national preserve is the crossroads of Texas' most interesting ecosystems: where coastal plains meet desert sand dunes, and cypress swamps stand next to pine and hardwood forests. Growing here are 145 different tree and plant species, plus 20 rare and hard-to-find orchids. Entry is free and so is camping, though you'll need a permit from the visitor's center.
The park is broken into nine widely separated units that together total more than 105,000 acres. Several of the units are linked by narrow, sinuous corridors that follow creeks and rivers. The Big Thicket National Preserve Visitor Center, 30 miles north of Beaumont on US 69/287, has the same maps and trail info that are available online.
About 3 miles east of the visitor center on FM 420, the interpretive Kirby Trail (1.7 to 2.5 miles round-trip) is a good area introduction, cutting through swampy land that supports magnolias and cypress communities, as well as slope forest with beach and tall, tall, tall loblolly pines. You can continue on to see cacti on the Sandhill Loop Trail (2-mile round-trip extension). About 5 miles northwest off US 69/287, the Sundew Loop Trail (1 mile round-trip) provides a look at bizarre carnivorous plants (four of North America's five species grow here). Look for wildflowers on this trail in late spring to summer.
Visitors are allowed to camp and hike anywhere in the preserve, with the normal restrictions applying (like sleeping away from water sources and packing out everything).