Port_of_Seattle The Port of Seattle is a port district that runs Seattle's seaport and airport. Its creation was approved by the voters of King County, Washington, on September 5, 1911, authorized by the Port District Act. It is run by a five-member commission. The commissioners' terms run four years. In 2005, the Port of Seattle was the 5th busiest port in North America by twenty-foot equivalent units (TEU) of container ship traffic and the 46th busiest in the world.