The present name, adopted in 1877, was given on account of the Sioux Indian agency being located there.

As of the census[1] of 2000, there were 237 people, 95 households, and 70 families residing in the township.

There were 95 households, out of which 28.4% had children under the age of 18 living with them, 71.6% were married couples living together, 2.1% had a female householder with no husband present, and 25.3% were non-families.

20.0% of all households were made up of individuals, and 12.6% had someone living alone who was 65 years of age or older.

About 2.8% of families and 4.7% of the population were below the poverty line, including 12.1% of those under the age of eighteen and none of those 65 or over.