The Columbia District was a fur trading district in the Pacific Northwest region of British North America in the 19th century. Much of its territory overlapped with the disputed Oregon Country. It was explored by the North West Company between 1793 and 1811, and established as an operating fur district around 1810. The North West Company was absorbed into the Hudson's Bay Company in 1821 under which the Columbia District became known as the Columbia Department. The Oregon Treaty of 1846 marked the effective end of the Hudson's Bay Company's Columbia Department. Early years Beginning in 1807, David Thompson, working for the North West Company (NWC), explored much of what would become the Columbia District. In 1811 he located Athabasca Pass, which became the key overland connection to the emerging fur district. The American Pacific Fur Company (PFC) founded Fort Astoria near the entrance of the Columbia River and began to counter the interior NWC trade posts. Funded largely by German-American merchant John Jacob Astor, the company men had previously sailed around Cape Horn on board . During the War of 1812, the Pacific Northwest was a distant region of the conflict. Prior to the war, both companies operated in the region peaceably with each other. News of a coming British warship put the American company into a difficult position. In October 1813, management met at Fort Astoria and agreed to liquidate its assets to the NWC. arrived the following month and in honor of George III of the United Kingdom, Fort Astoria was renamed to Fort George. North West Company In 1815 the North West Company's business west of the Rocky Mountains was officially divided into two districts, the older New Caledonia District in the northern interior, and the Columbia District to the south. Also in 1815 the New Caledonia district began receiving the bulk of its annual supplies by sea from the lower Columbia River rather than overland from Fort William and Montreal. By 1820 the North West Company operated six posts on the lower Columbia River and its tributaries, including Fort George (Astoria), Fort Nez Percés, Fort Okanogan, Spokane House, Flathead Post, and Kootanae House. Under the North West Company the Columbia District was bounded, roughly, by the southern edge of the Thompson River on the north, and by the southern and eastern limits of the Columbia River basin. North and west of the Thompson was the