It's actually not that many. There are two 70mm prints at Arclight Hollywood (one of which is the Dome), and one or two at The Landmark. There are only 16 total 70mm prints of The Master, so the rest are in New York or traveling around to other areas. At least seven more cities get it in 70 tomorrow and I'm sure they're trying to add other cities if they can find the right rooms.
Obviously, 70mm is the only acceptable format if you have that option. So do NOT wait to see it (or see it again) in the format.