PNLA is the oldest regional library association in the United States and the only binational association in North America. Members come from Alaska, Alberta, British Columbia, Idaho, Montana, Oregon, Washington, and beyond. Since 1909, PNLA has provided a professional and social forum for librarians, library workers, and library supporters throughout the vast Pacific Northwest region.

PNLA promotes increased communication, joint advocacy, open debate, networking and support, and information sharing through its many special projects and initiatives including: Jobs Board, Conference, Young Readers Choice Award, Leadership Institute, and PNLA Quarterly.