Johnson Island is a island located in LaSalle County, Illinois. It appears on the Marseilles USGS 7.5-minute topographic quadrangle. The nearest populated place is Seneca, approximately 2.6 miles to the E.
LaSalle County · Illinois
Johnson Island is a island located in LaSalle County, Illinois. It appears on the Marseilles USGS 7.5-minute topographic quadrangle. The nearest populated place is Seneca, approximately 2.6 miles to the E.