Statewide, other Allen Townships are located in Darke, Hancock, and Ottawa Counties.

[5] The town was named for Daniel Allen, one of the first settlers to the area.

Allen was one of the first thirteen citizens to vote in the township, and was one of the first trustees.

[5] One of the township's first settlers was Angus Clark; his son Shepard became a leading farmer in the township, and the Clark family property is today a local landmark known as "The Fort".

The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.