The township is divided into two nearly equal parts by the West Branch Susquehanna River.

The township is named for the descendants of Charles Grogan, later written as "Grugan", an Irish immigrant and American Revolutionary War veteran from Lancaster County.

The earliest known settlers of the region were John Baker Atkin and James Burney.

34.6% of all households were made up of individuals, and 15.4% had someone living alone who was 65 years of age or older.

There were no families and 5.6% of the population living below the poverty line, including no under eighteens and none of those over 64.