Butterflies of Putnam County
- Presents photos and species accounts of butterflies found within the county.
- http://www.butterfliesandmoths.org/map?dc=44&_dcc=1&si=36

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

Water Resources of Putnam County
- Factsheet providing information on water resources and drinking-water quality in the county.
- http://ohioline.osu.edu/aex-fact/0480_69.html