In the 1840s, the united states had a dispute over the oregon country with

spain.

great britain.

france.

mexico.

Great Britain

Explanation:

In the 1840s the United States wanted the area of the Oregon Country for itself, the problem was that Britain also occupied the area. Both countries started to negotiate on the issue and agreed that the border should follow the 49th parallel except Vancouver Island that should belong to Britain.

b. great plains

hope this

answer; i believe the correct answer is (the willamete valley);