Michigan's public libraries are divided into 6 class sizes based on total population served.
Class 1 Libraries: serve 3,999 or less
Class 2 Libraries: serve 4,000-6,999
Class 3 Libraries: serve 7,000-11,999
Class 4 Libraries: serve 12,000 - 25,999
Class 5 Libraries: serve 26,000-49,999
Class 6 Libraries: serve 50,000+