NWMLS monthly statistical reports and news releases summarizing housing activity for Western Washington. The Northwest Multiple Listing Service, is the largest full-service MLS in the Northwest. Based in Kirkland and owned by its member brokers, it currently encompasses more than 2,000 companies with approximately 26,000 sales associates. Together, they serve 17 counties, mostly in western Washington, plus Grant, Kittitas and Okanogan counties in the central part of the state. NWMLS recently added service to Clark County with the opening of an office in Vancouver.