Amwell Township is a 44-square-mile plot of steep ravines and grassy pasturelands planted with alfalfa, trefoil and timothy in the southwestern corner of Pennsylvania. It’s home to some 4,000 people, most of whom live in villages named Amity, Lone Pine and Prosperity.

From some views, this diamond-shaped cut of land looks like the hardscrabble farmland it has been since the 18th century, when English and Scottish settlers successfully drove away the members of a Native American village. Arrowheads still line the streambeds. Hickory trees march out along its high, dry ridges. Box elders ring the lower, wetter gullies. The air smells of sweet grass. Cows moo. Horses whinny.

From other vantages, it looks like an American natural-gas field, home to 10 gas wells, a compressor station — which feeds fresh gas into pipelines leading to homes hundreds of miles away — and what was, until late this summer, an open five-acre water-impoundment chemical pond. Trucks rev engines over fresh earth. Backhoes grind stubborn stones. Pipeline snakes beneath clear-cut hillsides.

The township sits atop the Marcellus Shale Deposit, one of the largest fields of natural gas in the world, a formation that stretches beneath 575 miles of West Virginia, Pennsylvania, Ohio and New York. Shale gas, even its fiercest critics concede, presents an opportunity for the United States to be less dependent on foreign oil. According to Wood Mackenzie, an energy-consulting firm, the Marcellus formation will supply 6 percent of America’s gas this year, a figure expected to more than double by 2020.

About five years ago, leases began to appear in the mailboxes of residents of Amwell Township from Range Resources, a Texas-based oil company seeking to harvest gas through hydraulic fracturing. “Fracking,” as it is known, is a process of natural-gas drilling that involves pumping vast quantities of water, sand and chemicals thousands of feet into the earth to crack the deep shale deposits and free bubbles of gas from the ancient, porous rock. Harvesting this gas promises either to provide Americans with a clean domestic energy source or to despoil rural areas and poison our air and drinking water, depending on whom you ask.

On Nov. 21, the Delaware River Basin Commission, which involves four states — Pennsylvania, New Jersey, New York and Delaware — will vote on rules governing fracking in the river’s watershed, which supplies some 15 million people with drinking water. The states most affected will be New York and Pennsylvania, which sit on the Marcellus Shale, where the gas is closest to the surface.