Elizabeth II is the Queen regnant of sixteen independent states and their overseas territories and dependencies. Though she holds each crown and title separately and equally, she is resident in and most directly involved with the United Kingdom. She is currently the second longest serving head of state in the world.
The 16 countries of which she is Queen are known as Commonwealth realms, and their combined population is over 129 million. In practice she herself wields almost no political power in any of her realms.