With a P.O.D. in the mid-18th or early-19th Century, the Americas of the 20th Century must have multiple (at least 5, preferably more) stable, sovereign, English-speaking countries, at least one of which must be inhabited by an Anglophone population of significant Native American heritage. Bonus points if there is also a country inhabited primarily by free Black people (though this does not mean that the countries need to be racially segregated ethno-states).