The Louisiana Purchase State Park encompasses 37.5 acres (15.2 ha) of forested wetlands, a landform which is regionally in decline due to agricultural development practices that include draining such areas.

[1] The Louisiana Purchase State Park is located at the eastern end of Highway 362, southeast of Blackton, Arkansas, at the tripoint junction of Lee, Monroe, and Phillips counties.

The inscription reads: "This stone marks the base established November 10, 1815, from which the lands of the Louisiana Purchase were surveyed by United States engineers.

President Thomas Jefferson commissioned the Lewis and Clark Expedition, which traveled west along the Missouri and associated rivers, eventually reaching the Pacific Coast, from 1804 to 1806.

The L'Anguille Chapter of the Daughters of the American Revolution at Marianna, Arkansas, began a campaign to memorialize the spot, culminating in the placement of the stone marker and a dedication ceremony on October 27, 1926, the 111th anniversary of the point's establishment.

[2] One forgotten feature of the dedication ceremony was that four local landowners each gave deeds for 2 acres (0.81 ha) of land surrounding the point, which would have created an eight-acre park.