The 322-acre (130 ha) state park has been operated by the Missouri Department of Natural Resources under a lease agreement with the L-A-D Foundation since 1984.

[6] Grand Gulf was declared a National Natural Landmark in 1971 as an excellent example of karst topography and underground stream piracy.

An uncollapsed part of the original cavern roof spans 250 feet (76 m), creating one of the largest natural bridges in Missouri.

A watershed of 28 square miles (73 km2) feeds into the gulf which itself drains into a cave entrance at its eastern end.

[6] Dye traces have shown that water entering the cave in Grand Gulf emerges 1 to 4 days later at Mammoth Spring in Arkansas, 9 miles (14 km) distant.