vancouver, washington is a united states city, just north of the columbia river in the state of washington. it is directly north of portland, oregon and south of vancouver, british columbia. both cities were named for george vancouver, a british explorer and sea captain. the city of vancouver includes fort vancouver, begun by the british hudson's bay company in 1824. it was made part of the united states on june 15, 1846, as part of the oregon treaty. it is the fourth largest city in washington state.