Dakota County was formed in 1855 and was named after the historic Dakota Sioux tribe. Area Page: Eastern North Nebraska AreaCounty Seat: Dakota City NebraskaLicense Platte Prefix: 70Census 2010: 21,006Cities Towns in the County: Dakota City NebraskaSouth Sioux City NebraskaCounty Map with Cities: Dakota County MapWebsite - County: Dakota County Nebraska Official Website