The Pierce County Library System (PCLS) is a library system serving the resients of Pierce County, Washington. As of 2006, PCLS has 17 branches and several bookmobiles serving more than 500,000 people in unincorporated Pierce County and 14 cities and towns which have annexed to the system for library service. It circulates more than 5 million items annually, hosts seasonal youth storytimes, teen clubs, programs for youth and adults, an active summer reading program, and has expanded into online interaction using social software.