Butterflies of Mercer County - Presents photos and species accounts of butterflies found within the county. www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/chklist/states/counties/oh_107.htm
Mercer County Ground-Water Resources - Factsheet providing information on ground-water resources in the county. ohioline.osu.edu/aex-fact/0490_54.html
Water Resources of Mercer County - Factsheet providing information on water resources and drinking-water quality in the county. ohioline.osu.edu/aex-fact/0480_54.html
