Monroe County Library SystemMCLS offers a variety of electronic services including circulation, online catalog of materials, online journals and databases. Currently, children ages 0-14 make up 18.9% of the county’ population, teens ages 15-19 comprise 7.1% of the population, and senior citizens account for 13.7% of the population. Just as the ages of our patrons vary, so do their reasons for coming to the library.