Butterflies of Clark County - Presents photos and species accounts of butterflies found within the county. - http://www.butterfliesandmoths.org/map?dc=298&_dcc=1&si=36
Clark County Environmental Data - Index to program areas, educational information, newsletters and events available through Ohio State University Extension. - http://clark.osu.edu/
Clark County Ground-Water Resources - Factsheet providing information on ground-water resources in the county. - http://ohioline.osu.edu/aex-fact/0490_12.html
Clark County Water Resources - Factsheet providing information on water resources and drinking-water quality in the county. - http://ohioline.osu.edu/aex-fact/0480_12.html