One of those, Dakota, contained the area north of the Minnesota River where it altered its flow from southeast to northeast.

In 1853 the first settler had homesteaded an area on the northeast run of the river, and the following year the settlement of Saint Peter was platted there.

Seeing the inflow of settlers into the areas adjoining the river, on March 5, 1853, the territorial legislature partitioned off the lower portion of Dakota County to form a separate entity.

It was named for Joseph Nicolas Nicollet (1786-1843),[4] a French explorer whose maps of the area had been instrumental in the territory's development.

[5] Significant fighting occurred in the county during the 1862 Dakota War, most notably at the Battle of Fort Ridgely.

Since 1976 the county has selected the Democratic and Republican Party candidates in equal measure in national elections (as of 2020).

It has backed the nationwide winner in every election since 1980 except for 2004, and even then, losing Democrat John Kerry only beat incumbent Republican George W. Bush in the county by just 108 votes and a 0.61% margin.