Mid-Columbia, serving an area of 160,000 residents, has a collection of 480,000 books and periodicals; in addition, there are 8,000 CDs, records, cassettes and other audio materials, as well as 16,000 video items, such as DVDs and VHS tapes. Internet terminals are available for use by the general public.

Staffing consists of 75 employees, of whom 14 are fully accredited librarians, plus volunteers. The system comprises10 branch libraries, plus one bookmobile. Annual expenditures on the library collection total $560,000. Patrons make 560,000 visits annually, and check out materials 920,000 times. Thirty-five percent of all check-outs are children's materials.

This facility houses administative offices. Branch libraries are listed below.