Berlin (/ˈbɜːrlɪn/ BUR-lin) is a city in Green Lake and Waushara counties in the U.S. state of Wisconsin. The population was 5,571 at the 2020 census. Of this, 5,435 were in Green Lake County, and only 89 were in Waushara County. The city is located mostly within the Town of Berlin in Green Lake County, with a small portion extending into the Town of Aurora in Waushara County.