Door County is the largest county in Wisconsin, it is a very beautiful and unique part of the state. On the map, it's the little finger(peninsula) on the northeast part of the state. Door County is located on a peninsula located between Green Bay and Lake Michigan. From the city of Sturgeon Bay to Gill'sDoor County is the largest county in Wisconsin, it is a very beautiful and unique part of the state. On the map, it's the little finger(peninsula) on the northeast part of the state. Door County is located on a peninsula located between Green Bay and Lake Michigan. From the city of Sturgeon Bay to Gill's Lighthouses