So, I think it has been not so often times that threads about more ethnic-cultural groups migrating to US/North Americas has sprung up on this site. Though there were some rather remember-able (for me at least) ones, whether it's about more Germans or more Asians, or less Irishmen. There was also Avicenna's very original idea of a TL where muslims from worldwide constituting constituting 23/24% of US population, putting aside how actually doable that percentage can be(Wonder where the man is now....

).
However, while there have been notable exotic options for new ethnic groups in US, there are still many others that haven't yet covered. South East Asians, if received any attention, usually only (if understandably) the Filipinos and Vietnamese, which don't have as much pool of potential immigrants compared to, say, Indonesia and Thailand. Besides the non-Europeans, almost at all times people often neglected European candidates that can actually make things quite interesting like, say, French people. Imagine a US with a population of French-descended people that's at least as large as Italian-descended ones !

Also, I've got say that Africans have been always neglected as well in this case. No love for post-slave trade influx of Africans ??

Though certainly I'm aware the budget obstacle the Africans will face without external help....
So here is the challenge : with PoD no earlier than 1740, make a dominant state in North Americas, basically US/US analogue which has its largest ancestral group constitute no more than
13% of its population (besides obviously having more immigrant groups than OTL

), by 1990. As for geographical conditions :
1) The southern-most point of its continental southern border can't be beyond the northern most point of OTL Northern border of Mexican
State of Veracruz southward. Carribean possessions are allowed, but it can't be more than 50% of the Antilles (the number of islands-wise, not the total land area).
2) North of it, this US analogue can have them all if you would choose to make it so, however it's preferable that this scenario's North America still has a *Canada. Actually, the less this *US stretches northward also, the better. Realism comes first, though.
This *US' primary requirement is that it is to be primarily Anglophone. Don't care whether it be a Republic or Monarchy or a British Dominion or what you have, as long as the primary conditions are fulfilled.