Narrower Terms (12)

• Cache River Valley (Ill.)
• Des Plaines River Valley (Wis. and Ill.)
• Fall Creek River Valley (Ill.)
• Fox River Valley (Wis. and Ill.)
• Illinois River Valley (Ill.)
• Kankakee River Valley (Ind. and Ill.)
• Kaskaskia River Valley (Ill.)
• Kishwaukee River Valley (Ill.)
• Rock River Valley (Wis. and Ill.)
• Saline River Valley (Ill.)
• Sangamon River Valley (Ill.)
• Wabash River Valley