Impounded in 1978, the 2,830-acre lake is a tributary of the Little Miami River (state and national scenic river) and was created principally for flood control. There are a variety of habitats at Caesar Creek Lake from old growth woods to native prairie grassland plus restored wetland areas. The reservoir is surrounded by over 8,300 acres in the park, dominated by surrounding mature upland forest and early successional woodlands. Topography consists of broad flat uplands dominated by oak-hickory and beech-maple forest types. Streams form steep sided rock valleys and are the site of Northern Floodplain forest types.
Caesar Creek's 2,830-acre reservoir attracts many different water birds beginning in late winter or early spring. Species include Common Loons, Horned and Pied-billed Grebes, American Coots, and a variety of gulls. Many species of ducks have been recorded, including Mallard, American Black Duck, Gadwall, Northern Pintail, Blue-winged Teal, American Wigeon, Northern Shoveler, Ring-necked Duck, Canvasback, Common Goldeneye, Bufflehead, and Common and Hooded Merganser. When conditions are right, hundreds of waterfowl can build up in these open water areas. Vagrant gulls and terns are regular.
Spring migration can be excellent, with warblers and early nesters pouring into several large unbroken woodland tracts and throughout the gorge. Confirmed woodland nesters include the following "Species of High Conservation Priority in Ohio": Red-shouldered Hawk, Yellow-billed Cuckoo, Blue-winged Warbler, and Cerulean Warbler. Standing timber in and around the many coves of the lake yield Red-headed Woodpeckers, Prothonotary Warblers, and Tree Swallows.
Other priority species noted over the years include: Osprey, Bald Eagle, Northern Harrier, Sharp-shinned Hawk, Sora, Buff-breasted Sandpiper, Common Tern, Northern Saw-whet Owl, Purple Martin, Hermit Thrush, Dark-eyed Junco, Bobolink, and Eastern Meadowlark. Buff-breasted Sandpiper occurs annually.
Over 500 acres of tallgrass prairie habitat have been planted in the park. In addition several wetland restoration sites have been constructed in the park, ranging from vernal woodland pools to permanent prairie pothole wetlands. Over 60 acres of riparian habitat have been planted in bottomland hardwood trees over the past 10 years, mostly along the two major feeder creeks - Caesar Creek and Anderson Fork.
Bush honeysuckle and garlic mustard are problems in the woodlands; park staff, with volunteer assistance, have targeted them. Feral cats have been identified as a problem.