This river's widest point, 3 1/2 miles, is just north of Clinton, Iowa
[DOC] [TLE] Soil Survey of Clinton County, Iowa (1917) [PAR] Clinton County, Iowa, lies along the Mississippi River, about midway between ... 
bounded on the north by the loessial upland just described and on the south and 
... the alluvial bottoms widen out to about 3 miles, Harts Mill Creek en- tering the 
... county line to a point where the Iowan drift plain crosses it south of the Cherry... [DOC] [TLE] Layout 1 (Page 1) - Fulton, Illinois [PAR] crossing, the distance was only a quarter mile wide.