[3] Pennsylvania Route 33 is the most prominent highway serving Plainfield Township.

Pennsylvania Route 191 follows a southwest-northeast alignment through the southern and eastern portions of the township.

Pennsylvania Route 512 also follows a southwest-northeast alignment, but through the northern and western parts of the township.

As of the census[5] of 2000, there were 5,668 people, 2,130 households, and 1,637 families residing in the township.

18.6% of all households were made up of individuals, and 9.0% had someone living alone who was 65 years of age or older.

The township is served by the Pen Argyl Area School District.