Cass County has several library system which operate in the county. The Cass District Library is the largest library in the county,  it has branches located in one city and 2 villages around the county. Cass District Library is the library system which services Calvin, Howard, Jefferson, LaGrange, Mason, Milton, Newberg, Ontwa, Penn, Pokagon, Porter and Volinia Townships.

The Dowagiac District Library serves the City of Dowagiac, Wayne Township, and portions of Silver Creek, Keeler, and Bainbridge townships. Marcellus Township also operates their own library apart from the Cass District library to service the residence of the village of Marcellus and the Township of Marcellus.