[2] Dakota County is part of the Sioux City, IA–NE–SD Metropolitan Statistical Area.

In the Nebraska license plate system, Dakota County is represented by the prefix 70 (it had the 70th-largest number of vehicles registered in the county when the license plate system was established in 1922).

[4] Succeeding cultures of indigenous peoples lived along the Missouri River for millennia.

By 1775, the Omaha people had migrated west of the Missouri, where they established a major settlement, Ton-wa-tonga, (the Big Village).

From here, the Omaha controlled fur trading on the upper Missouri River with other tribes and with French-Canadian traders, often called voyageurs.

About one of every 14 residents has tested positive, mostly at Tyson's large meat packing plant in Dakota City.

As of the 2020 United States Census The racial makeup of the county was 43.3% non-hispanic white, 7.4% African American, 2.8% Asian and 40.8% hispanic.

As of the 2010 United States Census, there were 21,006 people and 7,314 households residing in the county.

As of the 2000 United States Census, there were 20,253 people, 7,095 households, and 5,087 families residing in the county.