Big Oaks National Wildlife Refuge — Public Lands Institute

Ordovician445 Mya

~445 Mya Upper Ordovician (Cincinnatian) limestone and shale bedrock, mantled by Illinoian glacial till that forms the flat, poorly drained flatwoods plain of the Muscatatuck Regional Slope (~150,000 years).

Epoch

Late Ordovician (Cincinnatian) bedrock beneath Pleistocene (Illinoian) till

Native lands Glossary →

Myaamia (Miami), Eel River Miami, and Waayaahtanwa (Wea) held the primary claim to southeastern Indiana, with Shawnee (Shawanwaki) and Lenape (Delaware) ranging and hunting the same country; the Miami, Eel River, and Wea ceded this tract to the United States at the Treaty of Grouseland (August 21, 1805), reserving the right to hunt and to tap maple sugar in the ceded land while the Miami retained their claim to the Wabash and its waters to the northwest.

Displacement & Tenure

Royce Cession 8: Treaty of Grouseland (August 21, 1805), by which the Miami, Eel River, and Wea ceded the southeastern corner of present Indiana to the United States, opening the tract to settlement ahead of statehood (1816). A second, twentieth-century dispossession followed when the War Department condemned roughly 56,000 acres of this farmland in December 1940 for the Jefferson Proving Ground: resident families were given 30 to 120 days to vacate, and the land passed permanently into federal ownership rather than returning to private hands.

Shadow History

Big Oaks is a military sacrifice zone reopened as a refuge. In December 1940 the Army cleared a farming community across some 56,000 acres, giving families 30 to 120 days to leave, to build the Jefferson Proving Ground, which test-fired more than 24 million rounds of ordnance from 1941 until it closed under BRAC in 1995. An estimated 1.5 million unexploded rounds remain across the ground, and from 1984 to 1994 the Army fired about 100,000 kilograms of depleted-uranium tank penetrators into a 2,080-acre impact area that still holds roughly 70,000 kilograms of depleted uranium, held under Nuclear Regulatory Commission possession-only license SUB-1435 (issued September 2019) with no full cleanup planned. The contamination is why the Fish and Wildlife Service can open only about 4,000 acres around Old Timbers Lake to the public, and only to visitors who sign an annual acknowledgement-of-danger waiver.

Ecology

A rare large block of Midwestern grassland, flatwoods, temporary wetlands, and young forest regrown across the abandoned proving ground, designated a Globally Important Bird Area; the refuge holds one of the largest breeding populations of Henslow's sparrow (Centronyx henslowii) in the world, along with regionally significant grassland and shrubland birds, the state-endangered crawfish frog (Lithobates areolatus), and over 200 bird and 46 mammal species.

Hydrology

Drains the headwaters of Big Creek and Otter Creek in the Muscatatuck River basin (East Fork White River, Wabash and Ohio watershed); Big Creek carries runoff from the depleted-uranium impact area, and soil, sediment, groundwater, and surface water have been monitored for depleted uranium twice yearly since 1984.

Acreage

50,000

GPS

39.0050° N, 85.3900° W

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