Definitions of "Southeast Asia" vary, but most definitions include the area represented by the countries (sovereign states and dependent territories) listed below. All of the states except for East Timor are members of the Association of Southeast Asian Nations (ASEAN). The area, together with part of South Asia, was widely known as the East Indies or simply the Indies until the 20th century. Christmas Island and the Cocos (Keeling) Islands[citation needed] are considered part of Southeast Asia though they are governed by Australia.[citation needed] Sovereignty issues exist over some territories in the South China Sea. Papua New Guinea has stated that it might join ASEAN, and is currently an observer. 

The Andaman and Nicobar Islands of India are geographically considered part of Southeast Asia. Eastern Bangladesh and the Seven Sister States of India are culturally part of Southeast Asia and sometimes considered both South Asian and Southeast Asian. The Seven Sister States of India are also geographically part of Southeast Asia.[citation needed] The rest of the island of New Guinea which is not part of Indonesia, namely, Papua New Guinea, is sometimes included so are Palau, Guam, and the Northern Mariana Islands, which were all part of the Spanish East Indies.[citation needed]
Are Palau and Guam also part of it?
 sometimes included so are Palau, Guam, and the Northern Mariana Islands