Question

What was the last country to challenge the United States' control of Oregon?

Answer 1

Great Britain

Explanation:

In the early 1800s (1818 - 1846, I believe), Great Britain and the United States occupied Oregon Territory at the same time. They were both allowed to settle in this area. This was known as a "joint occupation".

Later around 1845, the United States proposed that the territory be divided to halves for each country, at the 49th parallel. Britain refused, and American northerners felt America needed to be more aggressive in gaining territory.

The president of the U.S. at the specific time was James K. Polk, whose slogan became "54-40 or fight". This odd phrase refers to the latitude marking of which the United States was negotiating for. As can be seen from the slogan, if the U.S. did not get what they so desired, they would 'fight'.

Both countries had no motive to go to war, however. Instead, Britain agreed to divide the territory at the 49th parallel. The territory also referred to as Oregon Country would later become modern day Oregon and make up parts of surrounding states.

So to answer your question in a basic sentence:

Great Britain was the last country to challenge United States' control of Oregon Territory, until an agreement was devised and war was avoided.