Hardin Soil and Water Conservation District
- Provides local leadership in the conservation and wise use of soil, water and related resources through cooperative programs that protects, restores, and improves those resources.
- http://hardinswcd.org/

Butterflies of Hardin County
- Presents photos and species accounts of butterflies found within the county.
- http://www.butterfliesandmoths.org/map?dc=136&_dcc=1&si=36

Hardin County Environmental Data
- Index to program areas, educational information, newsletters and events available through Ohio State University Extension.
- http://hardin.osu.edu/

Hancock Soil and Water Conservation District
- Agency responsible for protecting the natural resources within the county that assists landowners in planning and applying conservation practices on their land.
- http://www.hancockswcd.org/

Hardin County Ground-Water Resources
- Factsheet providing information on ground-water resources in the county.
- http://ohioline.osu.edu/aex-fact/0490_33.html

Water Resources of Hardin County
- Factsheet providing information on water resources and drinking-water quality in the county.
- http://ohioline.osu.edu/aex-fact/0480_33.html