Source: Marcellus Shale Advisory Commission report.
http://stateimpact.npr.org/pennsylvania/2011/08/02/pennsylvania-drilling-map/...
The Bradford County Planning Commission has produced some of the best maps charting the growth of the natural gas industry in one of the industry’s busiest counties. Using information from the Department of Environmental Protection.
See http://www.bradfordcountypa.org/Natural-Gas.asp?specifTab=2