I remember, when I was in Ohio, there was a supermarket that claimed they had had contact with local farmers and growers for 20 years and they promoted local trade.
It was really cool, you could find 20 kinds of salads, 10 kinds of peppers, 7 kinds of apples, even 5 kinds of mint leafs
They had everything, as well as products from all around the world, like french cheese, Italian olive oil, organic coffee from African "fair trade" enterprises etc. I wasn't looking for no meat to grill behind the Howard Johnson I was staying at, but I'm sure they also had products from local butcheries.