The Council of Umbar, or informally the Council of Captains, refers to the Umbarean government that took hold after the Downfall of Numenor. The Last Sealord of Umbar had departed with Pharazon into the uttermost west, along with his son (for Umbar had dedicated a great portion of its treasure and fleet to the Great Armament). As a result, after the Downfall and the loss of the royal government of Numenor, there was no obvious leader to take command of the havens in a time of crisis. As a result, many pre-eminent families in Umbar (ranging from powerful mercantile elites to noble lines descended from Sealords of Old) formed the Council of Umbar, which on paper was an oligarchy composed of the ‘elite’ of Umbarean society, with them electing a leader for life among their number.

However, in practice, 5 major families consolidated support behind themselves, each with powerful ties to the Umbarean fleets, with power in the Council (and the election) often a matter of who could sway the majority of the fleet. Because of this power imbalance in favor of naval captains (or those who could command them) informally it was known as the Council of Captains.