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 city of Williamsport is a drilling hub in the Marcellus shale in north-central Pennsylvania.
It got a big boost in tax income from 2010 to 2011.
The city reported earlier this month that its business privilege and wage tax revenue increased $487,000 from 2010 to 2011.
Much of the increase is tied directly or indirectly to Marcellus drilling, said Councilman Jonathan Williamson.
The news was circulated by the Marcellus Shale Coalition.
The coalition also noted a growing trend in Pennsylvania to eliminate water tankers and to instead install temporary water lines to get fresh water to wells for hydraulic fracturing or fracking.
That eliminates hundreds of the truck deliveries of water for each well.