I wonder if "racism" can be used to refer to discrimination against people from other regions within the same country. According to the Oxford dictionary, the definition of "racism" is:
Prejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one's own race is superior.
So it is up to the definition of "race".
Each of the major divisions of humankind, having distinct physical characteristics.
However, people from other regions usually don't have different physical characteristics.
Is there any such word to refer to discrimination against people who were born and/or grew up in other regions within the same country?