The Savanna Army Depot was founded in 1917 to test and manufacture munitions in a 13,000 acre swath of land located in southwestern Jo Daviess County and northwestern Carroll County in northwestern Illinois.
The area contains about 7,000 acres of uplands including the largest remnant sand prairie in the state, and 5,500 acres of bottomlands and is listed as a statewide significant natural area by the Illinois Natural Areas Inventory. At least 47 Illinois endangered and threatened plant and animal species have been observed at the Depot.
In 1995, the Depot was placed on the Army's base closure list. It officially closed on March 18, 2000. The land is being divided between federal and state agencies and the Local Redevelopment Authority. The U.S. Fish and Wildlife Service will own and manage 9,857 acres, called the Lost Mound Unit of the Upper Mississippi River National Fish and Wildlife Refuge. The unit derives its name from a prominent geologic feature, Lost Mound, located in the adjacent bluffland. The Illinois Department of Natural Resources will receive 270 acres (Primm?s Pond and Beaty Creek areas). The Lost Mound Unit will be managed by the FWS in cooperation with the IDNR. The LRA plans to redevelop 2,932 acres. Only portions of the site are open to the public.
The Depot was used as an artillery test firing site from 1918-1919 and as an ammunition recycling, storage and testing facility from 1919-2000.
The site includes a broad sand terrace, and below it, the floodplain borders the Mississippi River.
With its diverse and extensive habitat, Lost Mound provides homes for large numbers of many important nesting Illinois bird species. Grasslands offer breeding sites for small numbers of Upland Sandpiper, Dickcissel, Bobolink, Vesper Sparrow and Henslow's Sparrow and copious Western and Eastern Meadowlarks and Grasshopper Sparrow. On a single day during summer, at least 200 singing Grasshopper Sparrow males likely can be found. Lost Mound is also one of the best places to find large numbers of breeding Common Nighthawk.
Shrubby areas in the grasslands attract breeding Loggerhead Shrike, Lark Sparrow, Orchard Oriole, Northern Mockingbird, Yellow-billed and Black-billed Cuckoo, Bell's Vireo, Willow Flycatcher and Blue Grosbeak.
Riparian woodland corridors offer breeding spaces for American Redstart, Northern Parula and Prothonotary Warbler. The bottomland woods also attract breeding Yellow-bellied Sapsucker, Brown Creeper, Wood Thrush and Rose-breasted Grosbeak.
At least 23 species of swans, geese and ducks use the area in March and April as well as in October and November during migration.
Several pair of Bald Eagles have nested in the region, and many more use the area in winter for foraging and loafing.
This site was chosen as an IBA because it met the criteria for Waterfowl, Raptors, Wading Birds and breeding Upland Sandpiper, Red-headed Woodpecker, Brown Creeper, Loggerhead Shrike, and Grasshopper Sparrow.
The Savanna Army Depot officially closed on March 18, 2000, as part of the Base Realignment and Closure Act. The former Depot included a total of 13,062 acres that have been transferred to four agencies: the Service; the Local Redevelopment Authority; the U.S. Army Corps of Engineers; and the Illinois Department of Natural Resources.