Investing in the drillers isn't the only way to play the Pennsylvania natural gas rush. Many banks in the Keystone state are flourishing from the flurry of economic activity surrounding the world's second-largest gas field.

The shale banks
Northwest Bancshares (Nasdaq: NWBI) is the 12th largest bank in the Pittsburgh area based on deposits, but that could soon change. Northwest collects $1 million a week in shale-related deposits, and that figure could be just the beginning. The company's CEO said the drilling boom is still in its "infancy," which suggests a growing deposit stream on the horizon.

FBR Capital Markets released a report calling Northwest Bancshares one of the best- positioned banks for the shale boom, with three others sharing its spotlight.

First Commonwealth Financial (NYSE: FCF) receives 96% of its deposits from shale counties.

FNB (NYSE: FNB) has only 63% of deposits coming from shale counties, but the bank has strong market share in some highly targeted counties. Analysts at FBR designate FNB as the bank with the brightest future in the region.  

S&T Bancorp (Nasdaq: STBA) also enjoys ample exposure to the shale boom. The small-cap bank has a network of 51 branches in some of the best gas-producing counties. Some are even suggesting that PNC (NYSE: PNC), which dominates Western Pennsylvania, might want to buy out S&T  to capitalize on its good fortune.  

The bottom line
Shale banks could be a good way to invest in the golden age of natural gas. Many of these banks could experience years of growth as the nation continues to lean on natural gas as a future energy source.