Why are the Australian states divided the way they are.?

Question

Why are the Australian states divided the way they are.?

Answer 1

The British colonists simply carved a crude line across the map of the country to divide it into relatively equal-sized parts

Answer 2

NSW and Victoria are divided based on the Murray Darling river, I think.

Originially, there were 2 states, NSW in the east and WA in the west. SA split from WA and later split into the Northern Territory. Tasmania or Van Diemen's land, Qld split from NSW because it claimed it was too far from Sydney to be properly governed by it.