Being a part of East Texas, the region is geographically centered on the Greater Houston and Beaumont–Port Arthur metropolitan statistical areas with a combined population of 7,662,325 according to the 2020 U.S.

In Southeast Texas and the rest of the Southern United States, small rivers and creeks collect into swamps called "bayous" and merge with the surrounding forest.

The Piney Woods extend into the northern parts of Southeast Texas, reaching as far south as the rice paddies and marshlands that lie between Houston and Beaumont.

[8] The highest point on the coast is at High Island, where a salt dome raises the elevation to around 40 feet (12 m) above sea level.

The 97,000 acre (390 km2) preserve boasts a varied ecology of piney woods, swamps, and coastal prairies.

[12] Two historically important routes cross the Big Thicket: to the north lies the old cattle route or Beef Trail, that ran from Tyler County to Louisiana; to the south is the Spanish Trail or the Atascosito Road, that parallels modern Highway 90 and Interstate 10 from Liberty to Orange.

The bay provides nursery and spawning grounds for large amounts of marine life and is important for both commercial and recreational fishing.

This area of unusually high lightning activity stretches from Houston eastward into Southwest Louisiana.

However, the unusual clustering of lightning around the developed areas of Houston, the Golden Triangle, and Lake Charles, Louisiana have led many researchers to believe that some combination of urban heat islands and air pollution are responsible for increasing the number of lightning strikes beyond even the already-high natural levels.

[25] Additionally, the Catholic Church in the United States has remained a prominent religious influence since Spanish colonization and missionary work.

[26][27][28] Among its largest cities in East Texas outside Houston, many still follow a rural Southern way of life, especially in dialect, mannerisms, and cuisine.

In the urban areas of Southeast Texas, energy, healthcare, manufacturing and technology are prominent industries.

Houston is the largest city and economic center of Southeast Texas, and it holds the third most Fortune 500 headquarters by concentration in the U.S. as of 2021.

Participants enjoy activities from running in Memorial Park to sailing on Galveston Bay and Clear Lake.

[31] There are a variety of highways stretching between the Greater Houston and Beaumont metropolitan areas, connecting the communities to the remainder of the Gulf Coast region of the United States, and the Texas Triangle.