Darke County Environmental Data - Index to program areas, educational information, newsletters and events available through Ohio State University Extension. - http://darke.osu.edu/
Darke County Ground-Water Resources - Factsheet providing information on ground-water resources in the county. - http://ohioline.osu.edu/aex-fact/0490_19.html
Water Resources of Darke County - Factsheet providing information on water resources and drinking-water quality in the county. - http://ohioline.osu.edu/aex-fact/0480_19.html