Post Apocalyptic North America

Yes, I decided to take it upon myself to create a map of North America reviving itself after some large catastrophe that almost causes the extinction of human kind, but humanity, as much as it buckles under the weight of the catastrophe, clings to life, order, and existence even if it means the world must experience a neo Dark Age.
Inspired by Walter M. Miller Jr.'s book, A Canticle for Leibowitz, I am now going to describe each established empire, domain, republic, and kingdom in this neo-Medieval North America.

The Kingdom of Baja is the quietest and least outspoken of the Four Great Empires, and was established by a group of survivors thought to be the Holy Messengers of the Lord over 500 years ago. In its infancy, it was constantly raided by mysterious Nomadic tribes that were said to roam the arid Central Plains of North America prior to the establishment of the Domain of Texovuma. Its capital, Nuevo Angelos, was founded on the ruins of a once great city built by the Ancients, and continues to be a vital part of the Kingdom as a large producer of knives and swords which are traded with both Nomadic tribes and the other Great Empires. It's ruled by a King and/or Queen as an absolute monarchy.

The Holy Domain of Texovuma is the smallest, yet most loudly outspoken of the Four Great Empires. It was founded by a former Nomad said to have found God after being taken prisinor by the Kingdom of Baja for several years following a failed raid on a small farming village. The Domain continues to preach the radical beliefs of their former Nomad founder, and find themselves constantly under threat from the other Great Empires and the surrounding Nomadic tribes. It's capital is the city of San Antony, named after a Saint of the Ancients. Its main export is silk, but always cuts the flow of its exclusive commodity to certain Empires when its demands are not met. It's ruled by a Holy Domain Chief as an absolute monarchy.

The Columbun Empire is, geographically speaking, the largest of the Four Great Empires. It was founded upon the ideologies and principles of a fabled creator of the Ancients way of life, known only as Columbus to the leader of the Seven Founders of the Great Columbun Empire. The Empire is constantly under attack by Nomad tribes from the North and South, but has found ways of coping with them appropriately using tactics of fear and intimidation.
Its capital is Columbus City, known most prominently for its trading of fish and lumber with its neighbours and counterparts. It's ruled by a Council of Seven elected by the Empires Noble Class as a republic and limited democracy.

The Vacith Republic is the oldest of the Four Great Empires, and is said to have been founded by a Saint of the Ancients who was abandoned by his Nomad parents in his infancy, and is said to have been raised by a pack of wolves in the urban ruins of a city once said to have been known as Victoria. After reaching adulthood he began to convert Nomads to his vision of life as it should be. Its capital, the city of Vancenii, was founded three years following the death of the founding Saint, on the decaying ruins of an ancient city, by his son who was the first of nine in a lineage of monarchs to come. The Vacith Civil War lead to the downfall of the monarchy and the establishment of the Vacith Republic by a group of religious revolutionaries. It's currently ruled by a Council of Twenty elected by the Republic's Noble and Middle classes as a limited democracy. Vancenii's largest trade commodity is stone chiseled directly from the face of great mountains.

The Nomad City State of Kazokankanus Ichi is the only known permanent Nomadic settlement located in the far Northern half of North America. It's ruled by a tribal Chieftain and is constantly invaded by rival Nomadic Tribes. Its origins are virtually unknown, but legend has it that it was founded by the first of the Nomadic Gazo Chief's shortly after the fall of the Ancients society. It's a continental hub for any diplomatic talks made between any of the Four Great Empires and whatever Nomad tribe is currently in possession of the City State. It's also a large hub for the trading of Nomadic artwork and slaves. It's ruled as tribal monarchy.