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.
Carol Collier, executive director of the Delaware River Basin Commission, is retiring next March.
She has headed the agency since August 1998.
One thing she wants to do before she steps down is "defining a strategy for natural gas in the basin."
The commission has banned natural gas drillingin the watershed since 2010. It has come under heavy fire for its action.
Click here to read the full story from NPR's StateImpact Pennsylvania.