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 in Pennsylvania has dropped to a 2.5-year low.
The Marcellus Drilling News says there are 66 rigs operating in Pennsylvania, down from 113 rigs at this time last year.
The change is because many energy companies are cutting back on natural gas wells like those found in Pennsylvania's Marcellus shale because of low prices. They are more interested in oil and wet-gas wells like those being developed in eastern Ohio.
The rig data comes from Baker Hughes, a well service company.
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