Alfsborg Township was organized on January 26, 1869, and named after Älvsborg County in Sweden.

As of the census[1] of 2000, there were 356 people, 126 households, and 108 families residing in the township.

The racial makeup of the township was 98.88% White, 0.28% Asian, 0.84% from other races.

There were 126 households, out of which 40.5% had children under the age of 18 living with them, 77.0% were married couples living together, 4.8% had a female householder with no husband present, and 13.5% were non-families.

10.3% of all households were made up of individuals, and 0.8% had someone living alone who was 65 years of age or older.