Through the Baranov era there was no defined border of Russian-America. Along the Pacific Northwest coast, Russia, Britain, the U.S., and Spain all had competing claims. As the British established themselves in what is today British Columbia, Canada, they became the primary foreign power competing with Russia for territory in the region.
In 1825 Britain and Russia agreed on a border between British Canada and Russian-America. Alaska's borders today are largely based on this agreement. In the Southeast, Russian-America's border to the south was the Dixon Entrance (54°40' in latitude). The border with interior Canada was the summits of the Coast Range mountains that separated the Pacific coast from interior Canada.
Britain was allowed to use the Taku and Stikine Rivers to access its territory in interior Canada. Later, Britain would briefly operate forts at the mouths of these rivers at Ft. Taku and Ft. Stikine, the only European settlements outside of Sitka in Southeast Alaska. Neither fort operated for very long. British merchants found it easier and cheaper to trade from the decks of ships than to maintain forts.
The 1825 agreement set the boundary between the rest of Russian-America and Canada at 141 degrees of longitude. Much of this area in the Interior and Arctic Alaska was land Russians had never entered and knew little of. At the time of the agreement, they were just starting to explore up the Yukon River from the Bering Sea coast.
North America in 1825