As the United States dominates the Eastern Seaboard, Louisiana is primarily the Maritime power of the Gulf Coast. It is a largely a collection of Creole merchants who set up ports on the edges of the southern bayous. The cities and towns are essentially marinas and flea markets, and largely informal. Not to the nomadic extent of the western herdsmen, but it's common to see open-air markets and ships rendered as sumptuously as houses. The main hub is the city of New Orleans, a sprawling city of canals that is the home to seats of government, important religeous figures, and a vast necropolis to bury the dead.
The city of New Orleans is one of the most important places in America, as it not only serves as the gateway between North and South America, but the Mississippi River is the primary access from inland America to the warmer seas. There used to be a few wars fought to control the city, especially to wrest it from the Voodoo practitioners who ran it, but the Midwest demanded that a peace be kept on the city, because sieges on the river and the city would mean a lapse in trade which could make the upper classes feel like petty country barons at best, and decimate the populations at worst.
Louisiana is also the primary trading partner with Texas. Texas has the port of Houston where it can trade things like leather-work, as they have very little interest in engaging with sea travel. Louisiana also makes a good intermediary buyer. The ruling Anderson family is not on good terms with its eastern neighbor, the Red River Territory. Although Texans and Louisianans are of mutually different faiths, the latter don't much care about that sort of thing, and don't really have anything the cowboys wants. Therefore, the mariners distribute the Texans' goods with the non-denominational world, and in turn bring sundry items to the Texans. All for a tidy profit, of course.