How did it ever come to be that people from the United States are considered to be "Americans," while those from Canada are "Canadian" and those from Mexico are "Mexican," when Canada and Mexico are both part of North America. In fact, the US seems to have appropriated the term for itself. When it's necessary to differentiate between people from South America and Central America, you might see references to North Americans, but largely, people from the United States are referred to as Americans. Is it because using a derivate of United States to refer to its people would be clumsy? Would we be United Statesians or United States of Americans? Neither of these work well so we claimed the whole thing for ourselves.