Q:

The word for discrimination against people from other regions within a country?

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".
Now, the definition of "race" is:

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?

A:

Provincialism seems appropriate. Wikipedia equates parochialism but the concept of parish might not translate so well around the world.
The second definition from Oxford Dictionaries fits well: 

Concern for one's own area or region at the expense of national or supranational unity.

A:

chauvinism, Merriam-Webster

undue partiality or attachment to a group or place to which one
  belongs or has belonged •regional chauvinism

We all know what a male chauvinist is, but chauvinism or chauvinist can be used in almost any context.
For example, an MIT student might say:

I am unabashedly a MIT chauvinist, especially when it comes to Harvard
  -- that playboy's school down the road.

You can have New York City chauvinists, Southern chauvinists...you name it; although chauvinist will sound peculiar in some contexts, the meaning will be clear. 
Origin:  See Nicolas Chauvin, Wikipedia:

Nicolas Chauvin (French: is a legendary, possibly apocryphal French
  soldier and patriot who is supposed to have served in the First Army
  of the French Republic and subsequently in La Grande Armée of
  Napoleon. His name is the eponym of chauvinism, originally a term for
  excessive nationalistic fervor, but later used to refer to any form of
  bigotry or bias (e.g., male chauvinism).

A:

This could also be termed Tribalism.
Definition of tribalism, from Merriam-Webster

1 :  tribal consciousness and loyalty; especially :  exaltation of the tribe above other groups
2 :  strong in-group loyalty

