The unincorporated community of Mifflinville along the Susquehanna is the main settlement in the township.

Hetlerville is a small unincorporated community in the eastern part of the township.

[3] Interstate 80 (Keystone Shortway) runs east and west through the township with an exit at Pennsylvania Route 339, southwest of Mifflinville.

The first European settlers probably arrived in the area that is now Mifflin Township in the late 1770s, although the exact date cannot be determined.

Mifflin Township historically did not have much industrial business, because of the lack of transportation until the construction of the North and West Branch Railroad.

The racial makeup of the township was 98.71% White, 0.18% Native American, 0.71% Asian, and 0.40% from two or more races.

Several small additions are being added to accommodate the increasing class size, and a major renovation on the existing portion will bring it up to code.