Washington is one of fifty states that make up the United States. It is located in the northwestern portion of the country.
While searching for Dr. Schenker (who had been kidnapped by H.A.R.M.) Cate Archer boarded a train in the state of Washington. There she was able to discover the location of a secret H.A.R.M. Underground Base hidden behind the Dumas Lumber Company. After locating the missing doctor, they both escaped by a nearby UNITY helicopter that was waiting to take them to safety.
Washington on Wikipedia