The park consists of 484 acres (196 ha) on Big Cypress Bayou, west of Caddo Lake itself, in Harrison County, near Karnack, Texas.

At the time, the tribes in the region were not a connected nation, instead being a large collection of close-knit, peaceful gathering communities.

[4][5] The Spanish established several Missions and trading-posts during the 1700s, and numerous epidemics caused by the European settlements virtually wiped out the Caddo that inhabited the area.

[6] In 1800, as part of the secret Treaty of San Ildefonso, Spain, who had been defeated in the Napoleonic Wars, was forced to return Louisiana to France.

In 1806, United States General James Wilkinson and Spanish Lieutenant Colonel Simón de Herrera attempted to negotiate establishing a border between the two nations.

It is believed that Caddo Lake was formed by the Great Raft acting as a natural dam, and the first studies of this were reported around 1806.

Land was donated by various institutions and individuals between 1933 and 1937, the bulk coming from a gift of 385 acres by Thomas Jefferson Taylor II.

Alligators, river cooters, frogs, snakes, raccoons, mink, coypu, beavers, squirrels, armadillos, and white-tailed deer inhabit the park.

Permanent residents that are commonly sighted are mourning dove, great blue heron, turkey vulture, black vulture, red-shouldered hawk, barred owl, red-bellied woodpecker, downy woodpecker, pileated woodpecker, blue jay, American crow, fish crow, Carolina chickadee, tufted titmouse, Carolina wren, eastern bluebird, northern mockingbird, red-winged blackbird, pine warbler, and northern cardinal.

The following historic site is located within 30 miles (48 km) of Caddo Lake State Park:[19][20][21]