Cincinnati's Abandoned Subway - A section of the Cincinnati Transit site covers the abandoned and never-used subway tunnel under the city.
Columbus Underground - Drains, steam tunnels and abandoned buildings in the state capital.
Grave Addiction - A site mainly focussing on cemeteries and hauntings, but with some pages devoted to abandoned building as well.
Illicit Ohio - Abandoned buildings, steam tunnels, transit tunnels and drains of central Ohio.
Ohio Exploration Society - Site of a group of Ohio explorers featuring accounts of some abandoned buildings, mostly creepy, and an online store.
Ohio Lost - A few explored abandoned buildings are presented along with other sections on 'haunted' places and the like.
Ohio Trespassers - A nicely arranged site features a variety of hospitals, asylums and other abandoned fun in Ohio.
Ohio University Urban Exploration - An Ohio-University based explorer's brief guide to a variety of local attractions, from tunnels to drains to buildings.
SBNO Abandoned Amusement Parks - A well-put-together guide to standing but not operating amusement parks around Ohio.
UC Tour - A good map and a nice tour of the tunnels under the University of Cincinnati.
UnderOSU - The site banned by the Ohio State University administration, now back online at infiltration.org.