The Alto zip code serves most of Bowne Township, as well as portions of Lowell Township to the north, Cascade Township to the northwest, and Caledonia Township to the west.  It also serves a very small area of Campbell Township in Ionia County around the community of Elmdale.  Alto, which means "high," received its name from being the highest point along the railroad line on which it is situated. The elevation is somewhat higher to much higher than the surrounding cities of Caledonia, Lowell and Middleville.