Fort Atkinson is a city in Jefferson County, Wisconsin, United States. It is upon the Rock River, a few miles upstream from Lake Koshkonong. The population was 12,579 at the 2020 census. Fort Atkinson is the largest city located very in Jefferson County, as Watertown is split in the company of Jefferson and Dodge Counties.

Fort Atkinson was named after General Henry Atkinson, the commander of U.S. forces in the area during the Black Hawk War (1832) against a unclean band of Sauk, Meskwaki and Kickapoo peoples. The city developed at the site of Fort Koshkonong, which was used during that war. A replica of the original 1832 stockade has been built just external town, although not at the native site. The fort was located to rule the confluence of the Rock and Bark rivers.

The settlement grew suddenly in the mid-19th century, after the migration of pioneers from the east, especially New York State and the northern tier. They were in the midst of the many migrants carrying New England Yankee culture west across the northern tier of states.

The archives and natural archives of Fort Atkinson and the surrounding Place are presented at the Hoard Historical Museum and National Dairy Shrine Museum. William Dempster Hoard founded the nationally distributed dairy farm magazine Hoard’s Dairyman in Fort Atkinson in 1885. The museums intensify the Frank and Luella Hoard House, the Dwight and Almira Foster House, and the Knox Research Library and Archive. The Dairy Shrine ration of the perplexing portrays the past, present, and future of the dairy industry.