The First Federation was a political and military organization. First contact with the organization was made in the 23rd century.

Very little was known about the origins, deployment and population of the First Federation. The first encounter took place in 2266, when the USS Enterprise seemed to cross into First Federation space, destroying a marker buoy in the process.

Shortly thereafter, the Enterprise encountered the massive flagship of the First Federation, the Fesarius. Charged with violating their territory, the Enterprise and its crew were threatened with destruction. However, after a series of bluffs and counter-bluffs, it was later discovered that the encounter had been a test, designed by the Fesarius' captain, Balok. A cultural exchange was proposed, with Enterprise crewman Dave Bailey remaining on board the Fesarius. (TOS: "The Corbomite Maneuver")

The location of the First Federation was depicted on a Federation star chart. (TNG: "Conspiracy")

Trade between the First Federation and various Alpha Quadrant species continued into the 24th century, with tranya being a major export - Quark's on Deep Space 9 served the beverage. (DS9: "Facets")