This area encompasses the whole of Lake Koshkonong and surrounding wetland habitats, including nearby Lake Koshkonong Marsh State Wildlife Area, Rose Lake, and Red Cedar Lake State Natural Area. Habitats include shallow lakes, streams, emergent and submergent marsh, and floodplain forest.
Lake Koshkonong is a major staging area for migrating waterfowl, hosting tens of thousands of ducks in the spring. Ruddy ducks are particularly numerous. Wetland habitats support breeding populations of many species, including several of high conservation priority. The marshes support a large colony of black terns as well as least bitterns, blue-winged teal, marsh wrens, and yellow-headed blackbirds. Yellow-billed cuckoos, Acadian flycatchers, cerulean warblers and prothonotary warblers breed in the floodplain forests.