Provisional Government of Oregon in the context of Oregon pioneer history

Oregon Country was a large region of the Pacific Northwest of North America that was subject to a long dispute between the United Kingdom and the United States in the early 19th century. The area, which had been demarcated by the Treaty of 1818, consisted of the land north of 42° N latitude, south of 54°40′ N latitude, and west of the Rocky Mountains down to the Pacific Ocean and east to the Continental Divide. Article III of the 1818 treaty gave joint control to both nations for ten years, allowed land to be claimed, and guaranteed free navigation to all mercantile trade. However, both countries disputed the terms of the international treaty. Oregon Country was the American name, while the British used Columbia District for the region.

British and French Canadian fur traders had entered Oregon Country prior to 1810 before the arrival of American settlers from the mid-1830s onwards, which led to the foundation of the Provisional Government of Oregon. Its coastal areas north of the Columbia River were frequented by ships from all nations engaged in the maritime fur trade, with many vessels between the 1790s and 1810s coming from Boston. The Hudson's Bay Company, whose Columbia Department comprised most of the Oregon Country and north into New Caledonia and beyond 54°40′ N, with operations reaching tributaries of the Yukon River, managed and represented British interests in the region.

The U.S. state of Washington has 39 counties. The Provisional Government of Oregon established Vancouver and Lewis Counties in 1845 in unorganized Oregon Country, extending from the Columbia River north to 54°40′ north latitude. After the region was organized within the Oregon Territory with the current northern border of 49° north, Vancouver County was renamed Clark, and six more counties were created out of Lewis County before the organization of Washington Territory in 1853; 28 were formed during Washington's territorial period, two of which only existed briefly. The final five were established in the 22 years after Washington was admitted to the Union as the 42nd state in 1889.

Article XI of the Washington State Constitution addresses the organization of counties. New counties must have a population of at least 2,000 and no county can be reduced to a population below 4,000 due to partitioning to create a new county. To alter the area of a county, the state constitution requires a petition of the "majority of the voters" in that area. A number of county partition proposals in the 1990s interpreted this as a majority of people who voted, until a 1998 ruling by the Washington Supreme Court clarified that they would need a majority of registered voters. No changes to counties have been made since the formation of Pend Oreille County in 1911, except when the small area of Cliffdell was moved from Kittitas to Yakima County in 1970.

The Organic Laws of Oregon were two sets of legislation passed in the 1840s by a group of primarily American settlers based in the Willamette Valley. These laws were drafted after the Champoeg Meetings and created the structure of a government in the Oregon Country. At the last Champoeg Meeting in May 1843, the majority voted to create what became the Provisional Government of Oregon. Laws were drafted by the committee and accepted by a popular vote in July. These laws were reformed by a second version in 1845.

The Organic Laws were based on the laws of Iowa Territory and compartmentalized the government into three branches consisting of an executive branch, a legislative branch, and a judiciary. Once the Oregon Territory was formed in 1848, the territorial government took control of the laws and invalidated only one provision of the Organic Laws. On February 14, 1859, Oregon became a state and the Oregon Constitution became the legal framework for the state.