For the more information about the air resources of the National Park Service, please visit http://www.nature.nps.gov/air/.


Johnson County, IL

Heron Pond-Little Black Slough Natural Area
Heron Pond-Little Black Slough Natural Area, a National Natural Landmark in Johnson County, IL.

National Natural Landmarks in this county include:


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Please remember, National Natural Landmarks (NNLs) are not national parks. NNL status does not indicate public ownership, and many sites are not open for visitation.

Last Updated: June 28, 2012