From FamilySearch Wiki
- Washington Territory was created 14 February 1859 when State of Oregon was admitted to the union on the same day.
- The territory contained entire what is now state of Washington, northern part of Idaho and northwest portion of Montana (west of the continental divide.)
- The territorial capital was Olympia. It is now state capital of the State of Washington.
- Idaho Territory was created 4 March 1863 and contained all that is now State of Idaho, annexing the Washington Territory's portion of Idaho and Montana.