The St. Charles City-County Library is a separate taxing district that serves all of St. Charles County. The Library is supported by a property tax established by the voters of St. Charles County. Approximately 90% of the Library's revenue is generated by property tax. The maximum tax the Library may collect is $0.26 per hundred dollars of assessed valuation. Therefore, the owner of a $100,000 home would pay approximately $49.00 per year to the Library . The fiscal year for the Library is July 1 through June 30.
The Library operates under the jurisdiction of Missouri State Law. The Board of Trustees, consisting of nine members, oversees the operation of the Library. Under State Law for City-County Libraries, the St. Charles County Executive appoints five trustees and four trustees are appointed by the Mayor of St. Charles.
The St. Charles City-County Library was established on August 1, 1973 by a merger of the Kathryn Linnemann Library of St Charles and the St. Charles County Library District. It includes 3 regional branches which have larger collections and subject specialists, 4 general purpose branches, 2 Library Express, and 3 mini branches. The Library also provides an Outreach Service to nursing homes, retirement centers, the homebound, and the jail. The Library provides special collections and services in the areas of Local History and Genealogy, Business & Public Management, Consumer Health, Government Documents, and Nonprofit Services. The Library does not have a "headquarters" or "main" library; instead it distributes resources throughout the County and utilizes the vast resources of the St. Louis Metropolitan area to provide specialized materials. The St. Charles City-County Library does not serve specific municipalities within St. Charles County. It establishes branches in areas of greater population and mini branches in more remote areas. Along with facilities, the St. Charles City-County Library makes an active investment in cooperative programs to develop a dynamic informational infrastructure for St. Charles County residents.