Another interesting geographically focused product is rhubarb and the 9 square mile Rhubarb Triangle: https://en.wikipedia.org/wiki/Rhubarb_Triangle

At one point they grew 90% of the worlds forced rhubarb (a special kind of rhubarb grown indoors).

Weird that rhubarb is native to Russia and yet I've never seen it commercially grown there. My folks had a few plants grown in our ogorod, and made a delicious drink out of it. But now that I live in the city, I don't see any rhubarb jelly or drinks in the supermarkets.

You and dreen should start a Rhubarb Fact Club: https://news.ycombinator.com/item?id=17118067

And > 90% of America's wild blueberries come from Washington County, Maine.

This is really interesting, thanks for sharing.