The answer is:
I might be a city in one of the 'stans.
Mary is the capital city of Mary Province in Turkmenistan
I might be a river or more in Australia.
The Mary River is a large river system in South East Queensland, Australia. [OP note: there are three Mary Rivers in different parts of Australia - reference.)
I might have once bifurcated cleanly
This is referring to the Virgin Mary, who gave birth after an 'immaculate conception'.
I might have colleges named after me.
There are many colleges and universities named after Mary (Ex: St.Mary's College)
I might be said to be covered in blood.
Reference to Bloody Mary
What can I be to gather such renown?
Because she is the mother of 'Jesus Christ'.