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 rigs working in Ohio's Utica shale has taken a big jump.
It has grown from 30 to 37 rigs, as of June 1, reports the Ohio Department of Natural Resources.
To date, a total of 693 Utica shale wells have been permitted. Of that total, 339 wells have been drilled.
A total of 102 wells are in production.
A total of 18 new permits were approved: eight in Harrison County, four in Belmont County, four in Carroll County, one in Columbiana County and one in Washington County.