State

States were semi-autonomous regions of countries which generally had broad powers over the affairs of their residents. The national government formed by the combination of the several states was often called the "federal government". (PROSE: Endgame) It was not the universal condition of governmental organisation on Earth, as some countries, like England, were not subdivided into states. Notable examples of countries that had states were the United States of America and Australia. Canada effectively had states, but called them "provinces". (TV: Children of Earth: Day Three) Amongst the things that states and provinces did was issue licence plates for motor vehicles. Sarah Jane Smith, for instance, kept an Ontario licence plate in her attic. (TV: Enemy of the Bane)

United States
States were so integral to the structure of the United States of America that the concept was enshrined in the very name of the country. States were headed by governors, who had authority over at least the penal systems. They could offer paroles to prisoners. This implied that states had their own bodies of laws and that people could be punished for breaking them. (TV: The New World)

The question of whether states could secede from the federal union was central to the American Civil War. After a long and bloody conflict, the answer to the question was determined to be "no". (PROSE: Blood and Hope) allowcachedresults=true categorymatch=US states% namespace=0 columns=5 format = ,\n* %PAGE%

Australia
Less was known about the organisation of the Australian nation, and the relationship of its federal government to its states. Australian states to which the Doctor or his friends and associates were known to travel included: allowcachedresults=true categorymatch=Australian states% namespace=0 columns=3 format = ,\n* %PAGE%

Mexico
The Doctor knew of some Mexican states, but it wasn't always because he knew of them through personal travel there.

Provinces
The difference between states and provinces was unclear. But at least in their power to issue license plates for cars, they seemed to occupy a similar level of authority.

Canada
Canada was a nation known to prefer the term province over state. Ontario was a province of Canada. (PROSE: Christmas in Toronto)