A special "Thank You!" for all my watchers, here is a map I made for the CSA and USA from my current diversion, the "Communist CSA"-verse! It includes all the state names and shows a very detailed border! I hope you enjoy!
This reminds me of an idea I had - of a CSA that wins the Civil War and successfully creates an empire in the "Golden Circle" area, but by the mid-twentieth century (having abolished slavery decades earlier, although perhaps just de facto), is in a severe decline, and is overthrown by black, Latino, and Native American leaders, as well as Communists and the like, who establish a radical leftist (although not necessarily Communist) "Federated States of America" (or some other name for a successor state). Does this bear any resemblance to your idea?
Well, cross out the Native Americans (which just ignored it while thinking it couldn't get worse) and increase the Communists' role in the revolution, add in an already weak from the get-go Confederacy [their original territory of course included the "neutral" states, the entirety of Virginia, Texas, the southern half of OTL's New Mexico and Arizona, as well as the states of South California and Sonora and the Neutral Strip (now part of OTL's Oklahoma)] and you have it!
They did... Santo Domingo is the former Dominican Republic. And as a note, Haiti was a territory before the revolution, since the CSA government wanted to exploit that third of Hispaniola and the black population there.
Then why not go for Hondorus, Cuba, or South of the Rio Grande? Anyways, the main issue is keeping the name of Haiti, which the southerners would not like keeping around. Is this socialist land more tolerant of French speaking Catholic-voodo blacks?
Cuba: At that time of expansion still Spanish, later under British protection
Mexico: Too strong
Haiti was just a small country with a direct land border, pretty easy to invade after you put quite a few troops on your own side of the border. And well, the CSA didn't keep the name Haiti, but it was re-adopted after the Socialist revolution. And well, the CSAS isn't officially atheist and accepted French as a regional language because of Haiti AND Louisiana.