Southeast Pennsylvania has a number of unique foods.
For the wider population, our most famous food that people enjoy is the Philly cheesesteak, thinly shaved ribeye steak, grilled on a flat top, with American (or preferably sharp provolone) melted either on top or mixed in, on a long Italian roll. Sounds pretty basic, but the ribeye keeps the meat tender and juicy with its fat content, and the proper roll balances the taste and texture correctly, and I think that local roll is the key, and what makes a tasty cheesesteak hard to find once you get too far from the area.
Most divisive is scrapple, which was traditionally a mix of leftover cuts of meat and organs ("everything but the squeal") of the pig, thickened with cornmeal, and formed into a loaf that looks like a meaty slab of uncured cement. Grilled up proper, it looks somewhat like a square hand formed sausage, but it's the grey mystery meat story that keeps people away. I was tortured too much by the story by taunting relatives as a kid, so I still don't eat this, but my wife and brother love it.
For local foods from my culture, the Pennsylvania Dutch have given us way more odd foods than just scrapple!
My favorite is shoo fly pie. This reminds me of my grammom every time I think of it! 🥰 It is a molasses pie (though our family uses table syrup for a more delicate flavor) that has a bottom treacle type layer and a cakey top layer, topped with crumbs like on a struesel/coffee cake. I've never seen anything like it anywhere else, but for Funny Cake, another PA Dutch pie, which is essentially a chocolate syrup/vanilla cake version of shoo fly. Both good, and local markets will sell a half/half version where you get half a shoo fly and half a funny cake together (cut and repackaged, not baked together).
The divisive food that is still pretty common is Lebanon bologna. It is a cured, smoked, and fermented beef bologna. Very smokey and a bit sour, it can be a strange combo to the uninitiated, and is also available in a sweet version, and even that sweet vs regular can be a matter of contention among fans.
There are a lot more odd PA Dutch foods like stuffed pig stomach, souse, our pot pie that is actually a soup, ham balls, but that stuff you generally have to seek out anymore.