Territorial autonomy is an important constitutional phenomenon, but because the sub-state entities that can be identified as territorial autonomies are relatively small, the phenomenon is often overlooked in systematic presentations of constitutional law. This is not to say that treatises of national constitutional law would completely lack information about territorial autonomies, but the internal functioning of substate entities, in particular, is not known to a wider audience. Yet at the same time, each sub-state entity operates on the basis of its own constitutional law in the broad sense of the term, whatever the normative nature of that constitutional law might be. Therefore, the inner normative lives of territorial autonomies deserve to be opened up for a systematic review, which is comprehensive and comparative in nature so as to point out similarities and differences between the various sub-state existences. The similarities may be fewer than the differences, but what is striking in this context is that each of the autonomies included in this inquiry are by and large constructed along common elements, those of the distribution of powers, participation, the executive power, and foreign relations. Incidentally, these elements seem to hold the answer to what it means to be autonomous, that is, what it means not to be an independent state and not a symmetrical part of the governmental structure of the state, but autonomous. Although territorial autonomy may be unknown to the regular constitutional scholar or practitioner, I am convinced that the information contained in this inquiry will be useful for anybody interested in this constitutional phenomenon. At the same time, the inquiry will be interesting and useful for those who deal with sub-state issues, such as law-makers, politicians and civil servants of sub-state entities and of such states in which they exist, because the detailed information and analysis contained in this inquiry may function as a point of reference when, for instance, the development of an existing sub-state entity is planned or when the creation of a new territorial autonomy is on the drawing board. A further purpose of this inquiry is to simply recognize this particular institutional mode of organization.