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 gas drilling rigs is declining in Pennsylvania and nationwide, due to low natural gas prices and increased interest in oil, the Associated Press reported this week.
There were 98 drilling rigs in Pennsylvania during the week of March 23, according to Bkaer Hughes, a company that monitor rig counts.
That's dropped from a peak of 116 rigs last summer.
Nationally, the number of gas drilling rigs was 652.
In late 2008, there had been 1,600 gas rigs.
The number of oil rigs has jumped from 200 three years ago to 1,317 last week.
Drilling rigs bore the holes and set the pipes, but all wells don't go into production immediately.
The natural gas boom is not over. Many companies are investing in pipelines and other distribution facilities.
Some companies including Oklahoma-based Chesapeake Energy Corp. have also shifted rigs and resources to Ohio to develop its liquid-rich Utica shale at a time when prices are so low for natural gas.
They are after the ethane, butane and propane that are very valuable.