Three highway interchanges provide access from US 15 to the township, while a fourth connects to Exit 236 on the Pennsylvania Turnpike.

[4] Yellow Breeches Creek forms the southern border of the township, separating it from York County.

Several unincorporated communities are in the township, including Grantham, Bowmansdale, Shepherdstown, Nantilly, Mt.

The campus of Messiah University is defined as a census-designated place for population statistics.

24.3% of all households were made up of individuals, and 9.4% had someone living alone who was 65 years of age or older.

Upper Allen Township residents are served by the Mechanicsburg Area School District.