Royal Huguenots colonies in North America

A lot would depend on the circumstances. If say you had ~800,000 French Huguenots settled in N America, say half the total, then there is a significantly more substantial obstacle to either British or America conquests of the French colonies. Possibly not enough to stop it totally given the number of English speaking settlers and possibly the greater naval and industrial strength but you could end up seeing either a substantial French speaking minority, say a Canada on steroids, or possibly a sizeable independent French state.

It would require that France stays religious more tolerant and allows this acceptance of Huguenots in the colonies for the foreseeable future as at any point that it ends there is great potential for rebellion by the probable Huguenot majority majority in N America.

The other obvious butterfly, with a much larger French settlement in its colonies, is that the English colonists are going to be a lot more aware of the need for defence so the stance of the hard liners in the OTL revolution in the colonies, that they will contribute nothing towards this, is likely to be far more bitterly opposed, both in Britain and the colonies themselves. Therefore you might see the English colonies staying loyal until such time as they probably form an independent kingdom, say ~1850-60. They are likely, while directly British or afterwards to take some lands from the French simply because, unless there continues to be massive French settlement the English speakers will outnumber them. However you could have a clear French speaking state established in say modern Canada possibly with more of the Great Lakes. I think Louisiana is less likely to stay French because historically settlement was concentrated in Canada more and because its possession, especially New Orleans and control of the Mississippi, is going to be more important to the English settlers seeking to move west from the eastern coastal colonies.

A lot would again depend on the details. Its not impossible for Louisiana to survive in full but I suspect this wouldn't be the case. If so ultimately it might surpass the English states in population simply because it has room for expansion and they do not. However I think more likely a larger Canada with an overwhelming French population, say ~25-30 million by ~1900 and a somewhat smaller kingdom of America with say 60-75M in the same period.

  1)  Canada is more organised and possibly less problems with disease compared to southern Louisiana.  However as you say Louisiana has more longer term potential and Canada already has an established political establishment, which is conservative and Catholic so its unlikely to welcome a flood of heretics especially when it might outnumbered them pretty quickly.  Although St Lawrence and the Lakes possibly give a easier link into the interior?

  I suspect that Canada might be a longer term option for a surviving independent state as unless the French can hold the Ohio and Mississippi line they are likely to be out-populated by the English.  If so I can see the latter spreading west rather than north although the French might secure much of the old NW region, which would give them a much larger potential industrial base.  This might also mean that the border beyond the Mississippi might be at something like the 45th parallel or possibly even further south.

 2)  The Spanish won't welcome a large influx of Huguenots in N America and it would make a possible Bourbon monarchy in Spain less welcome in Madrid but there might not be a lot they could do about it.  The only way I could see Spain and Britain allied for more than a short period would be if you got a Napoleonic type situation where France simply looks so great a threat.

  As you say a French republican greater Canada and a royalist English America would make an interesting contrast to what we have here.

Why ? The emigration rates can not be compared between volontary (or proprietary-sponsored) emigration and royal policy of settlement. The Louisiana claim is huge, no shortage of land (or warmer climate) there. The one thing who could forbid it is an all-out naval war in the 1600' but, blessed France, thery were few at that time.

OK, misunderstanding here, I may not have been clear. I never thought the Huguenot migration can be held after 1685 and be a massive deportation of all the dissenting population, Moriscos-style. Rather, I put the hypothesis of an open migration, beginning in the late 16th c., as the solution to the religious issues in France is allowing the public protestant cult only in the colonies. The Royal Huguenot Colonies is an alternative to the Edict of Nantes, not the Edict of Fontainebleau. On such a timeline, the emigration of 800,000 people is not impossible.