What happened to Washington when Oregon became a state?

the eastern part of the territory was partitioned off into the new territory of Idaho,

Explanation:

When Oregon became a state, a few parts of the former Oregon Territory were added to Washington. In 1863, the eastern part of the territory was partitioned off into the new territory of Idaho, giving Washington the shape it has today. ... In the early 1870s, the people of Washington voted on statehood but remained divided.

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