King County Library System

Founded in 1942, the King County Library System (KCLS) is one of the largest and busiest library systems in the country. KCLS currently has 50 library branches spread throughout King County with more than 600,000 cardholders. In 2018, King County residents checked out almost 22 million items, including 4.8 million digital ebooks and audio books, making KCLS the number one circulating library for online downloads in the United States. Last year KCLS also had 10 million library visitors and 774,000 program attendees.


To inspire the people of King County to succeed through ideas, interaction and information.


A world where knowledge allows diverse communities to prosper and grow.



Diversity, Equity & Inclusion

Intellectual Freedom


Strategic Focus

We will create opportunities through meaningful connections.

We will do this by connecting people – individuals at all stages of life, families, communities and organizations – with:

  • Information and services to navigate life’s complexities and biases.

  • Equitable avenues to build the skills and knowledge needed for success.

  • One another to bridge differences and create communities of inclusion and belonging.

KCLS History



Voters establish the King County Rural Library District to provide library services to people in rural areas. Boulevard Park is the first to join KCLS.

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A second bookmobile, nicknamed "Celeste", joins the KCLS ranks. The first bookmobile, “Belinda”, went into service in 1944 to reach rural patrons.

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39 libraries are in operation, mostly in rented spaces. Services for children such as juvenile books, summer reading clubs, story hours, and book talks in schools, were a key aspect of the work.



$6 million bond passes, with plans to build 18 permanent libraries in the next 10 years.

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KCLS adopts a computerized circulation system.

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Ten cities vote to join KCLS, 11 more will join in the next 3 years.

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90% of King County residents have a KCLS library card.

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King County voters approve a $172 million Capital Bond to complete 16 new libraries, 11 expanded libraries, and 14 renovated libraries.



KCLS is named Library of the Year by Library Journal, the industry's highest honor.



KCLS celebrates its 75th Birthday with parties and events at each of the 49 libraries.

Read more about KCLS history on HistoryLink, Washington State's online encyclopedia.