Door County is the easternmost county in the U.S. state of Wisconsin. As of the 2020 census, the population was 30,066. Its county seat is Sturgeon Bay, making it one of three Wisconsin counties on Lake Michigan not to have a county seat with the same name. Instead it is named after the strait between the Door Peninsula and Washington Island. The dangerous passage, known as Death's Door, contains shipwrecks and was known to Native Americans and early French explorers. The county was created in 1851 and organized in 1861. Door County is a popular Upper Midwest vacation destination. It is home to a small Walloon population.

Sturgeon Bay is a city in and the county seat of Door County, Wisconsin, United States. The population was 9,144 at the 2010 census. The city is well-known regionally for being the center of the Door Peninsula, the namesake of the county.

Green Bay () is a city in the U.S. state of Wisconsin. The county seat of Brown County, it is at the head of Green Bay (known locally as "the bay of Green Bay"), a sub-basin of Lake Michigan, at the mouth of the Fox River. It is 581 feet (177 m) above sea level and 112 miles (180 km) north of Milwaukee. As of the U.S. Census Bureau's July 1, 2019 estimate, Green Bay had a population of 104,578, making it the third-largest in the state of Wisconsin, after Milwaukee and Madison, and the third-largest city on Lake Michigan, after Chicago and Milwaukee.Green Bay is the principal city of the Green Bay Metropolitan Statistical Area, which covers Brown, Kewaunee, and Oconto counties. Green Bay is well-known for being home of the Green Bay Packers of the National Football League.

Egg Harbor is a village in Door County, Wisconsin, United States. The population was 201 at the 2010 census. The village was incorporated in 1964, and is adjacent to the Town of Egg Harbor.