I was cruising in my Stingray late one night...(oops, wrong experience). I was cruising in the Green Weenie on I-8, heading for Maricopa. The sight of this hillside letter gave me an excuse to leave the freeway long enough to get a picture. This was taken from I-8 Exit 37 ("Roll").

The letter probably stands for "Antelope Heights" or "Antelope Acres" (housing areas at the base of the mountain) or "Antelope Union High School," which is close by.