According to the 2021 census gazetteer files, Prairie Green Township has a total area of 40.67 square miles (105.33 km2), all land.

52.60% of all households were made up of individuals, and 52.60% had someone living alone who was 65 years of age or older.

The entire township once made up part of the Wellington School District.

Established in 1872 as the Hope Congregation of the Disciples of Christ, it located in Prairie Green Township shortly thereafter.

The Pleasant Hill Methodist Church was once an active congregation in the Northeast part of the township, but closed in the early 1960s.