1792 - Gray 'discovers' mouth of the Columbia

        American sea captain Robert Gray claims the Columbia for the United States, but Vancouver  also 'discovers' the river at about the same time and claims it for England.  Gray's chart show that he had gone thirty-six miles upstream, while Vancouver did not sail past the mouth.  Nevertheless, the British held to their claim until 'the Oregon question' was settled during the Polk administration, in 1848.

(click here for more on the Columbia River)