You can watch the evolution of the USA from the beginning, including the formation of each and every county in the country. Its mesmerizing and I've been watching it on loop for the last 20 minutes.
I didn't know BC was ever part of the US. If my understanding from Wiki is right, it was jointly owned by the US and Britain and conceded with the Oregon Treaty. This was from lightly skimming the article so I may be way off.
Guess I never realized Oklahoma wasn't a state until 1907. Reading the first 30 years of Oklahoma history is FUCKED UP.