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 village of Owego in New York's Tioga County has voted to ban hydraulic fracturing or fracking for one year.
It is expected that New York will permit fracking in the Marcellus shale in five counties in the so-called Southern Tier near the New York-Pennsylvania border when local municipalities agree.
The counties are Broome, Chemung, Chenango, Tioga and Steuben.
To date, Owego is the second community to block drilling. The other is the city of Binghamton.
The village said its action was tied to drilling concerns and the need to develop a master plan to cope with flooding.