The state that border Washington (not Washington, DC) and Oregon to the east is the great state of Idaho.
Washington borders Idaho to the east and and Oregon also borders Idaho to the east.
Idaho
Nevada is further east than Idaho
Washington is bordered by Idaho to the east.
New Hampshire
Idaho borders Wyoming to the east and Montana to the northeast.
Idaho is east of Washington state and Oregon is south of it.
The pan handle of the state of Idaho borders WA state to the east.
Idaho borders Oregon from the east.
There are no states north of Idaho, Montana borders Idaho to the east, although because of Idaho's shape Montana does, for a section of southern Idaho, border Idaho's southeastern part.
Idaho is east of Oregon and Washington. Boise is the capital and most populous city in the U.S. state of Idaho.