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 Pittsburgh Post-Gazette carried a June 3 column by Patrick McShea looking at the hermit thrush, a woodland bird with a melodic song, and how it is being impact by Marcellus shale natural gas drilling.
The problem is that the drilling across northern and western Pennsylvania is fragmenting the forests where the thrush lives, says McShea, an educator at Pittsburgh's Carnegie Museum of Natural History.
It's not just the wells but the well pads, water storage facilities, pipelines and access roads, he said.
You can read his account by clicking here.