SUPERIOR TOWNSHIP, Mich. – Property owners in the upscale Glennborough neighborhood are suing the United States Postal Service to have their zip code switched from Ypsilanti to Ann Arbor after five years of unsuccessful attempts. “We are right in the middle of 48105 zip code,” said Marx. We’re in Ann Arbor Public Schools, Ann Arbor utilities, we get food delivery and everything from Ann Arbor yet we have an Ypsilanti zip code. The 48105 zip code areas are marked in green. Beyond issues with mail, switching to an Ann Arbor zip code could help improve property values and reduce insurance rates.