It Goes To Eleven
I got these coordinates from this thread at the Rift forum.
Ardent Domain - 5688, 9253
Ashora - 1726, 7176
Cape Jule - 7496, 11480
City Core - 6965, 9083
Dendrome - 3073, 4364
Eastern Holdings - 9515, 8344
Kingsward - 6855, 7765
Morban - 13888, 7780
Pelladane - 7136, 5657
Seratos - 11638, 5303 (Stand backwards on the end of the waterfall and drop down to the middle.)
Steppes of Infinity - 16803, 8219
It Goes To Eleven (Find the 11 Henges to gain access to Nomi)
Once you find all eleven and get the achievement, you can click on any of the Henge you just found and it will take you to Nomi who is located in the Dendrome. Upon arriving you will see a mini Stone Henge. By clicking on any of them you return to that henge. East of where you appear is a hut with Nomi inside. (see pics)
Ardent Domain - /setwaypoint 5688 9253
Ashora - /setwaypoint 1726 7176
Cape Jule - /setwaypoint 7496 11480
City Core - /setwaypoint 6965 9083
Dendrome - /setwaypoint 3077 4367
Eastern Holdings - /setwaypoint 9515 8344
Kingsward - /setwaypoint 6855 7765
Morban - /setwaypoint 13888 7780
Pelladane - /setwaypoint 7136 5657
Seratos - /setwaypoint 11638 5303 (Mid way down the waterfall from the top)
Steppes of Infinity - /setwaypoint 16830 8218