Montana is the clear leader in the number of letter geoglyphs in the western U.S. I have found 110 permanent glyphs plus two that look temporary. Of course, there may be more.
There are a few M's for the universities:
The most visited M (University of Montana in Missoula)
The largest M (Montana state University in Bozeman)
The only electric M (Montana Tech in Butte)
Another M (Western in Dillon)
The newest letters are in Great Falls - built in August 2007
Dozens of letters are for High Schools and a few are for universities and some are for towns.
Take the tour...