Looking ahead to 1850, my crystal ball shows me this...
After a generation or so, the NY/PA/VA settlers of Mesopotamia formed enough of their own identity to establish an independent republic. There's regional tension, mainly between the New Yorkers and Pennsylvanians on one side and the Virginians on the other, but it's held together. Disputes with Virginia over the central portion of Louisiana are a serious issue now - Virginia is the legal owner, but Mesopotamian settlers are a major element, especially in the northeast areas of West Virginia.
Georgia took advantage of Spain's post-Napoleonic troubles to buy Florida (which had seen many Georgian settlers move in, anyway). It and Carolina are currently wrangling over possession of South Louisiana.
Fear of New York and Virginia leads to unification of the Middle Atlantic republics. Atlantica is a very federal state, with common defense and a single currency the main glue holding it together on a national level.
New York has made out well. New Yorkers have settled Michigan and Superior, which are likely to become states of the Republic of New York before too long, a small New York/Sioux métis population is emerging in Minnesota and the republic has staked a claim to Shoshone Country, although it hasn't pressed the issue much so far.
New England survived a brief uptick in Back to Britain sentiment in the 1810s, but that movement has largely passed. Its main focus is on commerce, and Yankee ships play a major role in the whaling industry and, although less with each year, the slave trade as well. The growing Abolition movement is pressing for the establishment of a freed slave state in West Africa.
Britain secured New Orleans and a modest hinterland. Like Lower Canada, British Louisiana is a Francophone colony. The city of New Orleans has a small English population, but otherwise, there hasn't been much settlement since it was annexed by Britain.
On paper, at least, Russia has secured most of the Pacific Northwest. In reality, it controls a few coastal ports and some trading posts along the lower Columbia.
Northern Mexico is more secure in this timeline, since Anglo settlement is still centered on the vast Louisiana territory. Mexican forts and missions are being built in the east to solidify Mexican control before the Anglo flood reaches it.