One of those, Dakota, was partially subdivided in 1853 to create Blue Earth, Le Sueur, and Rice counties.

The county name was taken from the area's first farming settlement, started in 1855, near the present location of the city of Waseca.

That settlement name came from the Dakota word meaning "rich," a reference to the fertile soil in the area.

It is augmented by the Little Le Sueur, which drains the southeast part of the county.

The county terrain consists of low rolling hills, carved by drainages and dotted with lakes.

[7] The terrain slopes to the north and west, with its highest point near its southeast corner, at 1,240 ft (380 m) ASL.

[9] Waseca is one of seven southern Minnesota counties that have no forest ecosystems, only prairie and savanna soils.