Treaty of Saint Petersburg (1825)

The Treaty of Saint Petersburg of 1825 or the Anglo-Russian Convention of 1825, officially the Convention Concerning the Limits of Their Respective Possessions on the Northwest Coast of America and the Navigation of the Pacific Ocean, defined the boundaries between Russian America and British claims and possessions of the Pacific Coast, and the later Yukon and Arctic regions of North America. It was agreed that along the coast at the southern tip of Prince of Wales island (now known as parallel 54°40′ north) northward to the 56 parallel, with the island wholly belonging to Russia, then to 10 marine leagues (56 km) inland going north and west to the 141st meridian west and then north to the "Frozen Ocean", the current Alaska/Canadian Yukon boundary, would be the boundary.

Source: Wikipedia — Treaty of Saint Petersburg (1825) (CC BY-SA 4.0)