So, Trek is filled with alternate universes and timelines, but what TV show or movie leads to what timeline. it's a complicated tangle of various episodes, movies, and reboots.
I might create another list of non-canon materials and whether or not those transcend with each-other.
Anyway, my impression. (Forgive my use of DC terminology.)
Earth Prime (TOS, TNG, VOY, DS9)
Mirror Earth-Prime ("Mirror, Mirror" and all subsequent episodes)
New Earth (ENT, Trek '09)
Mirror New-Earth ("In a Mirror Darkly")
Why is Enterprise classified as a New Earth series? Frankly, since Into Darkness has the only reference to Enterprise having ever taken place, I figured that it would be the only place to count this as canon. Not to mention the whole advanced technology seems to be a staple of this universe.
In the interest of the why I put two Mirror Universes, here's why:
The universe presented in "In a Mirror Darkly" is different than the one presented in "Mirror, Mirror" and it's sequel DS9 episodes. Therefore, one must assume that each alternate Earth has a mirror universe duplicate, along with the infinite alternate timelines, each being a subset of these universes.