I am in Berks County, Pennsylvania, (right next door to Lancaster County and The Amish/Mennonnite communities), and we have many farmer's markets in our area, local and not too far away.
The most famous one I would say is, "Green Dragon". I have known people to come from out of state to visit Green Dragon. It is located off of Adamstown, PA, not sure of exact town. It is held every Friday from 9am to 9pm. Good Friday and Mother's day weekend are two of the most attended Fridays'. There is an animal auction every wee, (usually consisting of different types of birds, rabbits, guinea pigs, ducks, chicks, hamsters, etc. and a few goats). Alas, it is becoming more commercialized and is not the same as it once was, but is still a great place to visit if you like this type of thing and are in our area. (They not only sell food, but gadgets, clothes, purses, nail polish, perfume, plants, etc.).
Then we have many local farm markets to choose from weekly. The main one my husband and I go to is The Reading Farmers market located around The Reading Fairgrounds Mall.
We also have one in Shillington and West Reading.
OH, and let's not forget, Shady Maple....they have a great store/farmers market but most everyone comes for their smorgasboard. Love, love the buffet. This is another place that usually has many visitors from out of state.