Can't forget Noordeloos, Vriesland, Overisel, Drenthe, and Borculo. Been to Borculo a few times. Lotsa folks with Dutch/Frisian/Low German surnames in the area, including the (in)famously wealthy Van Andel and De Vos families of Grand Rapids.

Supposedly, the phrase "if you ain't Dutch, you ain't much" used to be common here, but I've never heard it used unironically. Likely died off with time.