King County Metro, officially the King County Department of Transportation Metro Transit Division or Metro for short, is the public transit authority of King County, Washington. It began operations on January 1, 1973, but can trace its roots to Seattle Transit, founded in 1939, and Overlake Transit Service, founded in 1927. Metro is the eighth-largest transit bus agency in the United States, carrying an average of 395,000 passengers each weekday on 215 routes. Metro employs 2,716 full-time and part-time operators and operates 1,882 buses.