Not a very large one, though I did try to germinate the Atlantic Giant variety that is suitable for this climate.
Unless the seedling starts off under plastic or glass in this temperate climate, the growing season is never long enough.
Some farmers here in this country have seen the profitable advantage in growing the commercial variety for the Hallowe'en festival. Even their professional growing varieties, however, do not exceed a medium sized pumpkin.
Good question. Hope someone here has grown a large one.