In 1792, Captain Robert Gray discovered Grays Harbor and entered the Columbia River, the first non-indigenous people to have done so. In 1803, President Thomas Jefferson sent the Lewis and Clark Expedition to explore the vast interior between the Missouri River and the Pacific Ocean. Although the expedition cemented American claims to Oregon Country, it failed to find a practical wagon route. It wasn't until the Oregon Trail began to be used by American settlers in the 1840s that British control of the Pacific Northwest, in the form of the Hudson's Bay Company, became challenged.