North America 1846: Oregon Treaty
War with Mexico encouraged President Polk to settle the Oregon dispute between the US and Britain. In June both countries agreed to the division of Oregon Country along the 49th parallel, with Vancouver Island falling to Britain.
17–18 May 1846 Capture of Matamoros▲
The United States Army of Occupation under General Zachary Taylor crossed the Rio Grande from Fort Brown into undisputed Mexican territory and occupied Matamoros (which had been abandoned by the Mexican garrison).
20 May–5 Aug 1846 Overthrow of Mariano Paredes▲
A liberal revolt starting in Guadalajara, Mexican Republic, encouraged General Jose Mariano Salas to mutiny in Mexico City and depose conservative President Mariano Paredes.
10 Jun–9 Jul 1846 Bear Flag Revolt▲
Encouraged by the nearby presence of a United States military expedition under John C. Fremont, American immigrants in the Mexican territory of Alta California rebelled, gaining control of Sonoma and raising a flag with the image of a bear and the words "California Republic" on it; they held out against Mexican opposition until the arrival of the US Navy.
15 Jun 1846 Oregon Treaty▲
The United Kingdom and the United States signed the Oregon Treaty, bringing an end to the Oregon boundary dispute by dividing the jointly occupied Oregon Country (known to British as Columbia Department) between the US and British North America. The treaty was negotiated by US Secretary of State James Buchanan, who later became president, and Richard Pakenham, British envoy to the US. In accordance with the treaty the border was set at the 49th parallel with the exception of Vancouver Island, which was retained in its entirety by the British.