CHESTER, Pa.

Twelve years ago, residents of this hardscrabble riverfront city watched its last supermarket shut down. As poverty deepened and businesses left, Chester was officially designated one of about 6,500 “food desert tracts” by the United States Department of Agriculture. This means the heavily low-income population of 35,000 lacked easy access to healthy, affordable food and people had to commute to other places to buy groceries. “I had to hire someone to drive me to markets in other towns; that’s the way I shopped,” said Sylvia Powell, a longtime resident.

That changed in late September when a full-fledged supermarket named Fare & Square opened in the very building that had housed the last profit-driven supermarket. Anyone driving down Ninth Street, a grimly tattered boom-to-bust boulevard, suddenly encounters Fare & Square gleaming and bustling like a mirage, like the supermarkets in the middle-class towns flourishing farther off in the Delaware Valley.

It was opened as a creative outpost, a “nonprofit supermarket” conceived by Bill Clark, executive director of Philabundance, a hunger relief organization well known to the poor and needy on the streets of Philadelphia, 15 miles northeast. Isolated and recession-battered, Chester needed “a real Phoenix story,” Mr. Clark decided — in the form of a market rooted in community pride and healthy, low-priced food.