The county was created by theMinnesota Territory legislature on February 20, 1855, using areas partitioned fromRice,Blue Earth, andLe Sueur counties.Owatonna, the settlement of which had commenced in 1854, was named the county seat. The county was named forFranklin Steele, a prominent early resident of the territory.[3]
TheStraight River rises inFreeborn County and flows northward through the central part of Steele County, continuing intoRice County on the north. TheSouth Branch of the Middle Fork of the Zumbro River rises in Steele County and flows eastward intoDodge County. The county terrain consists of low rolling hills, etched with drainages, completely devoted to agriculture where possible.[5] The terrain slopes to the east and north, with its highest point near the midpoint of its south border, at 1,293 ft (394 m) ASL.[6] The county has an area of 432 square miles (1,120 km2), of which 430 square miles (1,100 km2) are land and 2.7 square miles (7.0 km2) (0.6%) are water.[7]
TheStraight River flows northward through the county, and theLe Sueur River flows through its southwestern corner. The Middle Fork of theZumbro River rises in NE Steele County.[8]
As of the2000 census, there were 33,680 people, 12,846 households, and 9,082 families in the county. Thepopulation density was 78.3 per square mile (30.2/km2). There were 13,306 housing units at an average density of 30.9 per square mile (11.9/km2). Theracial makeup of the county was 95.19% White, 1.07% Black or African American, 0.10% Native American, 0.85% Asian, 0.02% Pacific Islander, 1.65% from other races, and 1.12% from two or more races. 3.76% of the population were Hispanic or Latino of any race. 38.6% were ofGerman, 18.5%Norwegian, 5.2%Czech and 5.1%Irish ancestry.
There were 12,846 households, out of which 35.50% had children under the age of 18 living with them, 59.50% weremarried couples living together, 7.40% had a female householder with no husband present, and 29.30% were non-families. 24.60% of all households were made up of individuals, and 10.30% had someone living alone who was 65 years of age or older. The average household size was 2.57 and the average family size was 3.08.
The county population contained 27.90% under the age of 18, 8.20% from 18 to 24, 29.00% from 25 to 44, 21.60% from 45 to 64, and 13.30% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 97.50 males. For every 100 females age 18 and over, there were 95.00 males.
The median income for a household in the county was $46,106, and the median income for a family was $53,981. Males had a median income of $36,366 versus $25,054 for females. Theper capita income for the county was $20,328. About 4.20% of families and 6.20% of the population were below thepoverty line, including 7.10% of those under age 18 and 7.10% of those age 65 or over.
Steele County voters have traditionally votedRepublican. In only one national election since 1964 has the county selected the Democratic Party candidate (as of 2024[update]).