<P> The Oregon Country was originally claimed by Great Britain , France , Russia , and Spain ; the Spanish claim was later taken up by the United States . The extent of the region being claimed was vague at first , evolving over decades into the specific borders specified in the US - British treaty of 1818 . The U.S. based its claim in part on Robert Gray 's entry of the Columbia River in 1792 and the Lewis and Clark Expedition . Great Britain based its claim in part on British overland explorations of the Columbia River by David Thompson and on prior discovery and exploration along the Coast . Spain 's claim was based on the Inter caetera and Treaty of Tordesillas of 1493 -- 94 , as well as explorations of the Pacific coast in the late 18th century . Russia based its claim off its explorations and trading activities in the region and asserted its ownership of the region north of the 51st parallel by the Ukase of 1821 , which was quickly challenged by the other powers and withdrawn to 54 ° 40 ′ N by separate treaties with the US and Britain in 1824 and 1825 respectively . Spain gave up its claims of exclusivity via the Nootka Conventions of the 1790s . In the Nootka Conventions , which followed the Nootka Crisis Spain granted Britain rights to the Pacific Northwest , although it did not establish a northern boundary for Spanish California , nor did it extinguish Spanish rights to the Pacific Northwest . Spain later relinquished any remaining claims to territory north of the 42nd parallel to the United States as part of the Adams - Onís Treaty of 1819 . In the 1820s , Russia gave up its claims south of 54 ° 40 ′ and east of the 141st meridian in separate treaties with the United States and Britain . </P>
<P> The Oregon Country was originally claimed by Great Britain , France , Russia , and Spain ; the Spanish claim was later taken up by the United States . The extent of the region being claimed was vague at first , evolving over decades into the specific borders specified in the US - British treaty of 1818 . The U.S. based its claim in part on Robert Gray 's entry of the Columbia River in 1792 and the Lewis and Clark Expedition . Great Britain based its claim in part on British overland explorations of the Columbia River by David Thompson and on prior discovery and exploration along the Coast . Spain 's claim was based on the Inter caetera and Treaty of Tordesillas of 1493 -- 94 , as well as explorations of the Pacific coast in the late 18th century . Russia based its claim off its explorations and trading activities in the region and asserted its ownership of the region north of the 51st parallel by the Ukase of 1821 , which was quickly challenged by the other powers and withdrawn to 54 ° 40 ′ N by separate treaties with the US and Britain in 1824 and 1825 respectively . Spain gave up its claims of exclusivity via the Nootka Conventions of the 1790s . In the Nootka Conventions , which followed the Nootka Crisis Spain granted Britain rights to the Pacific Northwest , although it did not establish a northern boundary for Spanish California , nor did it extinguish Spanish rights to the Pacific Northwest . Spain later relinquished any remaining claims to territory north of the 42nd parallel to the United States as part of the Adams - Onís Treaty of 1819 . In the 1820s , Russia gave up its claims south of 54 ° 40 ′ and east of the 141st meridian in separate treaties with the United States and Britain . </P>
in the early 1800s what four countries claimed land in oregon
in the early 1800s what four countries claimed land in oregon
Great Britain France Russia Spain
Great Britain France Russia Spain