Chesapeake Energy Corp,the Oklahoma-based firm is the No. 1 driller in Ohio.
Rig Count Interactive Map by Baker Hughes, an energy services company.
Shale Sheet Fracking, a Youngstown Vindicator blog.
The Ohio Environmental Council, a statewide eco-group based in Columbus.
Earthjustice, a national eco-group.
People's Oil and Gas Collaborative-Ohio, a grass-roots group in Northeast Ohio.
Concerned Citizens of Medina County, a grass-roots group.
No Frack Ohio, a Columbus-based grass-roots group.
Fracking: Gas Drilling's Environmental Threat by ProPublica, an online journalism site.
Pipeline, blog from Pittsburgh Post-Gazette on Marcellus shale drilling.
Allegheny Front, environmental public radio for Western Pennsylvania.
The number of drilling permits in Ohio for the Utica shale is up to 464 through Dec. 1.
That includes 188 wells that have been drilled, the Ohio Department of Natural Resources reports.
A total of 45 Utica wells are in production.
Ohio has 27 drilling rigs at work.
The newest permits include eight in Carroll County and one in Harrison County.
Carroll is No. 1 in Ohio with 167 permits.
Columbiana has 66; Harrison, 55; Jefferson, 31; Guernsey, 24; Monroe, 20; Noble, 17; Mahoning, 15; Portage, 14; Stark, 13; Tuscarawas, 12; and Belmont, 11.