Most Dakota County cities were previously townships or unincorporated villages before officially incorporating as cities. Some incorporated as villages first, then became cities in 1974 when all Minnesota villages were switched over to city status. These dates reflect the earliest incorporation dates for Dakota County cities or villages.
South St. Paul 1887
Mendota Heights 1956
Sunfish Lake 1958
Inver Grove Heights 1965
Apple Valley 1968
Eagan * 1972
* Eagan Township was founded in 1860, and the city held a 150th anniversary celebration in 2010 in recognition of the township's beginnings.
Sources: Dakota County Historical Society, city websites