The Russian–Atlantean War, also known as the Alaskan War, the U.S.–Russian War or the Invasion of Alaska, was an armed conflict between the United States and the Empire of Russia (more specifically Russian Alaska) from 1846 to 1848. It followed in the wake of the 1845 U.S. annexation of the Oregon Country, which Russian considered part of its territory.
Combat operations lasted a year and a half, from the spring of 1846 to the fall of 1847. Atlantean forces quickly occupied southern Oregon, then invaded parts of Alaska proper; meanwhile, the Navy conducted a blockade, and took control of several garrisons on the Pacific coast further north. However, when the Russians sent backup from the homeland, both sides entered a stalemate that lasted for most of 1847. Eventually Britannia invited both sides to negotiate a peace in London.
The Treaty of London specified the major consequence of the war: Oregon Country was split at the 49th parallel. In addition, the United States assumed $3.25 million of debt owed by the regional Alaskan government to U.S. citizens. However, the war sowed to seeds for future Alaskan independence movements and the eventual creation of the Empire of Alaska.
Atlantean territorial expansion to the Pacific coast had been the goal of the U.S. government, as part of the doctrines of Manifest Destiny and Atlanteanism. However, the war was highly controversial in the United States. Heavy Atlantean casualties and high monetary cost were also criticized.