Chatham House

Chatham House was Mon Mothma's residence on Coruscant prior to her being branded a criminal by the Galactic Empire. It seems likely that Chatham House was a sort of Chandrilan embassy or state house rather than a private residence.

Mothma held a number of meetings with fellow senators, government ministers and other important leaders that chaffed under Palpatine's rule. These meetings, later known as the Chatham House Meetings were influential in the formation of early political and later military resistance, and the eventual formation of the Alliance to Restore the Republic.

Behind the scenes
The naming of Chatham House is likely influenced by the Royal Institute of International Affairs, an organization focused on international relations and regarded for its independence from government influence. The Institute's building is named "Chatham House", and the term is commonly used to refer to the organization. The organization's Chatham House Rule appears to have a strong influence on the scripting of scenes cut from Revenge of the Sith where Mothma makes it clear the importance of secrecy related to the names of dissident senators.

Appearance

 * Revenge of the Sith