Since 1959, the Mid-Hudson Library System (MHLS) has acted to ensure the public's right to free access, facilitate economical resource sharing, and promote professional library services while working in partnerships with the independent public and free association libraries in New York's Hudson Valley. MHLS comprises libraries in five counties: Columbia County, Dutchess County, Greene County, Putnam County and Ulster County. The System's headquarters is in the city of Poughkeepsie.