Oregon Country in the context of "Provisional Government of Oregon"

The Mexican–American War, also known in the United States as the Mexican War and in Mexico as the United States intervention in Mexico, (April 25, 1846 – February 2, 1848) was an invasion of Mexico by the United States. It followed the 1845 American annexation of Texas, which Mexico still considered its territory because it refused to recognize the Treaties of Velasco, signed by President Antonio López de Santa Anna after he was captured by the Texian Army during the 1836 Texas Revolution. The Republic of Texas was de facto an independent country, but most of its Anglo-American citizens who had moved from the United States to Texas after 1822 wanted to be annexed by the United States.

Sectional politics over slavery in the United States had previously prevented annexation because Texas would have been admitted as a slave state, upsetting the balance of power between Northern free states and Southern slave states. In the 1844 United States presidential election, Democrat James K. Polk was elected on a platform of expanding U.S. territory to Oregon, California (also a Mexican territory), and Texas by any means, with the 1845 annexation of Texas furthering that goal. However, the boundary between Texas and Mexico was disputed, with the Republic of Texas and the U.S. asserting it to be the Rio Grande and Mexico claiming it to be the more-northern Nueces River. Polk sent a diplomatic mission to Mexico in an attempt to buy the disputed territory, together with California and everything in between for $25 million (equivalent to $798 million in 2024), an offer the Mexican government refused. Polk then sent a group of 80 soldiers across the disputed territory to the Rio Grande, ignoring Mexican demands to withdraw. Mexican forces interpreted this as an attack and repelled the U.S. forces on April 25, 1846, a move which Polk used to convince the Congress of the United States to declare war.

The United States of America was formed after thirteen British colonies in North America declared independence from the British Empire on July 4, 1776. In the Lee Resolution, passed by the Second Continental Congress two days prior, the colonies resolved that they were free and independent states. The union was formalized in the Articles of Confederation, which came into force on March 1, 1781, after being ratified by all 13 states. Their independence was recognized by Great Britain in the Treaty of Paris of 1783, which concluded the American Revolutionary War. This effectively doubled the size of the colonies, now able to stretch west past the Proclamation Line to the Mississippi River. This land was organized into territories and then states, though there remained some conflict with the sea-to-sea grants claimed by some of the original colonies. In time, these grants were ceded to the federal government.

The first great expansion of the country came with the Louisiana Purchase of 1803, which doubled the country's territory, although the southeastern border with Spanish Florida was the subject of much dispute until it and Spanish claims to the Oregon Country were ceded to the US in 1821. The Oregon Country gave the United States access to the Pacific Ocean, though it was shared for a time with the United Kingdom. The annexation of the Republic of Texas in 1845 led directly to the Mexican–American War, after which the victorious United States obtained the northern half of Mexico's territory, including what was quickly made the state of California.

Presidential elections were held in the United States from November 1 to December 4, 1844. Democratic nominee James K. Polk narrowly defeated Whig Henry Clay in a close contest turning on the controversial issues of slavery and the annexation of the Republic of Texas. This is the only election in which both major party nominees served as Speaker of the House at one point, and the first in which neither candidate held elective office at the time.

President John Tyler's pursuit of Texas annexation divided both major parties. Annexation would geographically expand American slavery. It also risked war with Mexico while the United States engaged in sensitive possession and boundary negotiations with Great Britain, which controlled Canada, over Oregon. Texas annexation thus posed both domestic and foreign policy risks. Both major parties had wings in the North and the South, but the possibility of the expansion of slavery threatened a sectional split in each party. Expelled by the Whig Party after vetoing key Whig legislation and lacking a firm political base, Tyler hoped to use the annexation of Texas to win the presidency as an independent or at least to have decisive, pro-Texas influence over the election.

Idaho (/ˈaɪdəhoʊ/ ) is a landlocked state in the Pacific Northwest and Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west; the state shares a small portion of the Canada–United States border to the north with the Canadian province of British Columbia. Idaho's state capital and largest city is Boise. With an area of 83,569 square miles (216,440 km), Idaho is the 14th-largest state by land area. The state has a population of approximately two million people; it ranks as the 13th-least populous and the seventh-least densely populated of the 50 U.S. states.

For thousands of years, and prior to European colonization, Idaho had been inhabited by natives. In the early 19th century, Idaho was considered part of the Oregon Country, an area which was disputed between the U.S. and the British Empire. Idaho officially became a U.S. territory with the signing of the Oregon Treaty of 1846, but a separate Idaho Territory was not organized until 1863, instead being included for periods in Oregon Territory and Washington Territory. The state was eventually admitted to the Union on July 3, 1890, becoming the 43rd state.

Johnson Creek is a 25-mile (40 km) tributary of the Willamette River in the Portland metropolitan area of the U.S. state of Oregon. Part of the drainage basin of the Columbia River, its catchment consists of 54 square miles (140 km) of mostly urban land occupied by about 180,000 people as of 2012. Passing through the cities of Gresham, Portland, and Milwaukie, the creek flows generally west from the foothills of the Cascade Range through sediments deposited by glacial floods on a substrate of basalt. Though polluted, it is free-flowing along its main stem and provides habitat for salmon and other migrating fish.

Prior to European settlement, the watershed was heavily forested and was used by Native Americans of the Chinook band for fishing and hunting. In the 19th century, non-Native American settlers cleared much of the land for farming, and the stream is named for one of these newcomers, William Johnson, who in 1846 built a water-powered sawmill along the creek. By the early 20th century, a rail line parallel to the stream encouraged further residential and commercial development. As urban density increased in the floodplain, seasonal floods grew more damaging. In the 1930s the Works Progress Administration of the federal government lined the lower 15 miles (24 km) of Johnson Creek with rock to control the floods. Despite this, the creek flooded 37 times between 1941 and 2006. Since the 1990s, regional planners have tried to reduce flooding by controlling stormwater runoff, creating stream meanders, reducing erosion, replacing impervious surfaces, and protecting riparian buffers.

The Territory of Oregon was an organized incorporated territory of the United States that existed from August 14, 1848, until February 14, 1859, when the southwestern portion of the territory was admitted to the Union as the State of Oregon. Originally claimed by several countries (see Oregon Country), Spanish "El Orejón" was part of the Territorio de Nutca (1789–1795), later in the 19th century, the region was divided between the British Empire and the US in 1846. When established, the territory encompassed an area that included the current states of Oregon, Washington, and Idaho, as well as parts of Wyoming and Montana. The capital of the territory was first Oregon City, then Salem, followed briefly by Corvallis, then back to Salem, which became the state capital upon Oregon's admission to the Union.

The Oregon boundary dispute or the Oregon Question was a 19th-century territorial dispute over the political division of the Pacific Northwest of North America between several nations that had competing territorial and commercial aspirations in the region.

Expansionist competition into the region began in the 18th century, with participants including the Russian Empire, Great Britain, Spain, and the United States. After the War of 1812, the Oregon dispute took on increased importance for diplomatic relations between the British Empire and the fledgling American republic. In the mid-1820s, the Russians signed the Russo-American Treaty of 1824 and the Russo-British Treaty of 1825, and the Spanish signed the Adams–Onís Treaty of 1819, by which Russia and Spain formally withdrew their respective territorial claims in the region, and the British and the Americans acquired residual territorial rights in the disputed area. But the question of sovereignty over a portion of the North American Pacific coast was still contested between the United Kingdom and the United States. The disputed area was defined as the region west of the Continental Divide of the Americas, north of Mexico's Alta California border of 42nd parallel north, and south of Russian America at parallel 54°40′ north. The British generally called this region the Columbia District and the Americans generally called it Oregon Country.