Polonia Township was originally settled chiefly by Polish settlers, hence the name.

As of the census[1] of 2000, there were 38 people, 14 households, and 11 families residing in the township.

The population density was 1.0 people per square mile (0.4/km2).

The racial makeup of the township was 94.74% White, 2.63% Asian, and 2.63% from two or more races.

21.4% of all households were made up of individuals, and 14.3% had someone living alone who was 65 years of age or older.