It seems like every week another E&P makes a move on the mighty Marcellus shale. Most recently, it was Newfield Exploration (NYSE:NFX) hitching up with Hess (NYSE:HES) to exploit 140,000 gross acres in Pennsylvania. With the Marcellus coming to the fore as one of the top destinations for domestic drilling, lots of companies are playing catch-up. Not Range Resources (NYSE:RRC).

Range pounced on this play early, having drilled 77 horizontal wells in the Marcellus to date. The company estimates that it has about 900,000 acres in the "fairway," or most prospective land within the broader play. In southwestern Pennsylvania alone, where about 320 industry wells have helped to delineate the shale resource, Range sees the potential for 3,900 horizontal well locations. Overall, the Marcellus will keep the company busy for a very long time.

In the third quarter, Range delivered another strong performance, with overall production up 13% over last year. The Marcellus is on track for 90 million to 100 million cubic feet per day of production by the end of the year, up from 26 million at the end of 2008. That number is set to double again in 2010, thanks to more custom-built Drake rigs being delivered by National Oilwell Varco (NYSE:NOV).

All-in costs came in at $4.69 per mcfe (thousand cubic feet equivalent), just a bit higher than when we checked on Range and Cabot Oil & Gas (NYSE:COG) in the first quarter. Range Resources remains a low-cost leader, with cash flow margins of 67% this quarter. That's not terribly far off from Ultra Petroleum (NYSE:UPL) territory. The fact that Ultra is also making moves on the Marcellus makes it a tougher call on which horse to back in this shale race. Let's put it to a vote, shall we? Take the poll then let us know your reasoning in the comments section below.

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Fool contributor Toby Shute doesn't have a position in any company mentioned. Check out his CAPS profile or follow his articles using Twitter or RSS. The Motley Fool's disclosure policy thinks Pennsylvania is a lovely state.