That it was incredibly lucky that British Columbia is part of Canada today.
It's 1857. The Hudson's Bay Company controls the land east of the Rocky Mountains. There is a British colony on Vancouver Island. However, what's now British Columbia wasn't under the control of anyone. Sure, there was a border agreement between Britain and the United States where the British gave up their claims on Washington and Oregon, but the status of the land north of the 49th parallel is still in question. The very real problem is that the area is largely unexplored and, apart from the First Nations, largely uninhabited by Brits or Americans. Both sides have fir trading posts on the Pacific coast, and the HBC administers them, but unlike the other side of the Rockies, the HBC has no land rights over the British Pacific.
Then, the apocalypse that changed everything - the 1857 Fraser River Gold Rush.
Tens of thousands of Europeans flooded into the interior, clashing with the First Nations as they went. Most of them were Americans. Although there was technically a "border" and technically you weren't allowed to cross it except by stopping in Victoria first, this was largely ignored.
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