Mayor of Plainfield, New Jersey: Mayors are sworn in on January 1 of the new year, so there are no overlaps in years unless someone has died in office or resigned.
References
Mayor of Plainfield, New Jersey Wikipedia(Text) CC BY-SA
Mayor of Plainfield, New Jersey: Mayors are sworn in on January 1 of the new year, so there are no overlaps in years unless someone has died in office or resigned.