What records that do exist could suggest human occupation dating back to the Clovis culture 13,400–12,700 years ago, with numerous era diagnostic points being found in all but one of the counties commonly considered to be in the Big Thicket.

The exposed surface soils are relatively recent, late Cenozoic Era, predominantly Miocene, Pliocene, Pleistocene, and Holocene Epoch formations.

It was during those warmer periods of submersion that alluvial and delta deposits from the streams and rivers of the continent laid down the succession of strata, each new layer burying and compacting the previous.

Longleaf pine-bluestem grass uplands are most extensive in northern areas, on higher elevation plateaus between streams and dry upper slopes, where the soils of the Catahoula, Fleming, Willis, and Bentley formations often have several feet of moderately coarse sand over an iron oxide clay or plinthite hardpan stratum.

Additionally, many areas clearcut for lumber have been replanted with rows of the faster growing, non-native slash pine (Pinus elliottii) eliminating much of the longleaf pine-bluestem grass uplands from Texas.

Although these areas receive the same rainfall as the rest of the region, water drains quickly in the deep sand which dries in the sun leaving an arid surface.

Ground cover is dominated by rushes, sedges (Rhynchospora and Scleria), and grasses including Andropogon, Aristida, Muhlenbergia, and little bluestem (Schizachyrium scoparium).

The closed canopy filters the light reaching the forest floor where an ample layer of leaf litter holds water, creating a mesic understory.

A rich diversity of wildflowers are found in slope forest such as three jack-in-the pulpits (Arisaema dracontium, A. quinatum, A. triphyllum), Indian pipe (Monotropa uniflora), and wake-robin (Trillium gracile).

Orchids include the yellow lady's-slipper (Cypripedium calceolus), spring coral-root (Corallorhiza wisteriana), whorled pogonia (Isotria verticillata), southern twayblade (Listera australis), crippled crane fly (Tipularia discolor), and three birds (Triphora trianthophora).

The major floodplains in the region were formed during the Wisconsin glaciation, when sea levels were low and great rivers cut deep and wide channels in the landscape.

The Trinity River basin in particular stands out in contrast to others with calcareous, relatively high pH, alkaline soils supporting vegetation that is seldom seen in other watersheds, including bois d'arc also called horse apple (Maclura pomifera), blueberry hawthorn (Crataegus brachyacantha), cedar elm (Ulmus crassifolia), and Texas sugarberry (Celtis laevigata).

Although baygall waters are generally shallow and torpid, they sometimes form small, highly acidic blackwater streams, slowly moving into the larger creeks and bayous.

These and swamp titi (Cyrilla racemiflora) are dominant and other common shrubs include southern bayberry (Myrica cerifera), water willow (Decodon verticillatus), red bay (Persea borbonia), and Virginia sweetspire (Itea virginica).

Other understory species found on the flats are creeping spot-flower (Spilanthes americana), Missouri ironweed (Vernonia missurica), lance-leaved water-willow (Justicia lanceolata), and inland sea oats (Chasmanthium latifolium).

The "corridor effect"[6] of traffic, both human (vehicles, tourists, and road crews) and birds and other animals, inadvertently dispersing seeds and roots along roadsides from other areas.

Examples include hog-nosed skunks (Conepatus leuconotus), red wolves (Canis rufus), ocelots (Leopardus pardalis), and jaguars (Panthera onca).

[32] Although once common in the Big Thicket, the American black bears (Ursus americanus) was the target of a concerted effort to extirpate them from east Texas in the late nineteenth century.

Carter reported that in 1883, he and a neighbor set out to exterminate the bears in the Tarkington Prairie area of Liberty County that preyed on their free ranging hogs in the forest.

"[32] They prey on natural populations of invertebrates, amphibians, reptiles, ground nesting birds, and rodents and are known to play a role in the transmission of disease including brucellosis, pseudorabies, and swine fever.

The Atakapa-Ishak (including the subgroups Akiosa, Akokisas, Bidai, Deadoses, and Patiri) occupied the Big Thicket area, living nomadically along the Gulf of Mexico in Southeast Texas and southwest Louisiana.

They left evidence of hunting camps and such, although the Big Thicket area itself does not appear to have been the site of any significant permanent settlements comparable to the Caddo mound builders to the north.

About the same time as the collapse of the Atakapa-Ishak people, the Alabama-Coushatta, originally two closely associated tribes living in adjacent areas of Alabama, began a westward migration about 1763 due to the encroachment of Europeans.

In the mid-nineteenth century the Big Thicket was sparsely populated by a few scattered inhabitants living in the woods off subsistence farming, hunting, and running free range hogs and cattle.

By the 1920s East Texas timber was nearing depletion and most of the operations practiced a cut-out and get-out policy and moved on, many to the Pacific coast, leaving vast areas of clear-cut forest behind.

He was not a conservationist, he advocated for sustainable forestry methods as a good business practice, including reforestation, maintaining soils, grasses, wildlife, and establishing parks.

A new Big Thicket Association was founded in 1964 by Lance Rosier and continued pushing for protected land and the governor appointed Dempsie Henley to head a proposal for a state park.

However, with changing officials in state elections, lackadaisical attitudes, opposition from timber firms, and several attempts without success, Henley enlisted the aid of U.S.

Claude McLeod, a biologist at Sam Houston State College, had been studying the Big Thicket for several years and completed a manuscript about the time a National Park survey team arrived in 1966 to develop the proposal.

The various ghost stories include reference to the Kaiser Burnout, long-dead conquistadors looking for their buried treasure, a decapitated railroad worker, and a lost night hunter eternally searching for a way out.