I believe this is the statement you are thinking of:
"Door County boasts more lighthouses (10), more miles of shoreline (250), and more state parks (5), than any county in the contiguous United States."

This is the count of lighthouses I know of:
1)Sherwood Point
2)Sturgeon Bay Ship Canal
3)Sturgeon Bay North Pierhead Light
4)Sturgeon Bay Dunlap Reef - light gone (house converted to a dwelling)
5)Old Baileys Harbor
6)Baileys Harbor Rear Range Light
7)Baileys Harbor Front Range Light
8)Cana Island
9)Chambers Island
10)Eagle Bluff
11)Pottawatomie Light on Rock Island
12)Pilot Island
13)Plum Island Front Range Light
14)Plum Island Rear Range Light

There are even more lighthouses if you count the entire Door peninsula.