Butterflies of Union County
- Presents photos and species accounts of butterflies found within the county.
- http://www.butterfliesandmoths.org/map?dc=207&_dcc=1&si=36

Union 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.co.union.oh.us/soil-water-conservation/

Union County Environmental Data
- Environmental information for developers.
- http://ohioline.osu.edu/aex-fact/0490_85.html

Water Resources of Union County
- Factsheet providing information on water resources and drinking-water quality in the county.
- http://ohioline.osu.edu/aex-fact/0480_80.html