This is Oregon Territory, during a five-year period shortly after the signing of the Oregon Treaty (extending the Canadian border to the Pacific Ocean on the 46th parallel) from 1848 to 1853.
There’s been various proposals to unite with BC as a country called Cascadia, including /r/cascadia. There’s already a national soccer (football) team, so it is to be taken seriously.
I took the liberty of excluding the parts of Montana and Wyoming west of the Continental Divide for the sake of simplicity. This was originally going to be a map of the entire Oregon Country, from the tip of Alaska to the Californian border, but combining statistics and rankings from two different countries (with different measurement systems) was too much work for a quick Reddit post.