[2] Allegany Township is unusual in that it uses a variant spelling of the word Allegheny more commonly associated with the state of New York in its name.

Cobb Hill, located in this township, is part of the St. Lawrence River Divide.

West-northwest of Cobb Hill is Rose Lake, which through the first half of the 20th century fed tributaries of both rivers, and therefore drained into both the Atlantic Ocean (via the St. Lawrence River) and the Gulf of Mexico.

[3] As of the census[4] of 2000, there were 402 people, 161 households, and 115 families residing in the township.

23.6% of all households were made up of individuals, and 11.8% had someone living alone who was 65 years of age or older.