Columbia comprises, more or less, OTL US states of Delaware, Maryland, Michigan, Pennsylvania, New Jersey, New York, Wisconsin, Northwestern Minnesota, Ohio, and the Canadian provinces of Ontario, Manitoba, Saskatchewan.
The Federal Republic of Columbia was established in 1786 with the union of the republics of New York, New Jersey, Pennsylvania, Maryland and Rhode Island. Originally Delaware, Connecticut, New Hampshire and Massachusetts joined as observers.
The republics, now named states, would surrender some of their sovereignty to the Federal government set at Philadelphia.
In 1792, the state of Rhode Island signs the New England Alliance, which would, eventually, lead to a conflict with the Federal Republic. That same year, Delaware formally joins the Federal Republic of Columbia.
In 1793, Rhode Island secedes from Columbia. The Columbian Congress passes an Act that forbids states to sign alliances with foreign nations, and harshening the conditions for any state to leave the Federation.
In 1812, Columbia declares war to the United Kingdom, for border problems in the east. Britain is pretty much involved against France in Europe and cannot react to the Columbian attack on Canada. New England, asked to participate in either side, declares neutrality.
In 1816, the British authorities in Canada surrender. Columbia annexes Michigan and Ontario and demands the independence of all British territories in northeastern North America. Britain grants independence of the territories over which New England offers protectorate status. All colonies accept protectorate but Quebec, which declares independence and alliance to Columbia.
In 1834, Columbia allied with Louisiana who was attacked by Virginia. The war ended in 1837 with the surrendering of Virginia. Neither Columbia nor Louisiana asked for territorial claims. Columbia was granted full passage on the Mississippi and Louisiana territory was preserved.
A bi-national commission was set in 1839 to explore and mark the limits between Louisiana and Columbia. The expedition finished in 1842 and both nations confirmed the limits at the Mississippi and the 40th parallel.
In 1824, an amendment banning slavery was introduced to the Federal Congress, but failed. Several states had already banned slavery, including New York, Pennsylvania and Michigan.
The amendment ran again in 1825 and 1826, and was finally approved in 1827: All slaves were emancipated, the owners were paid a compensation, and emancipated black slaves were given a free passage to Africa. Given that no African nation were accepting them, most former slaves end up in Ontario territories.
The Federative Republic of Columbia is composed by 15 states, including:
- New Jersey
- New York