Microscopic, spatially controlled, and highly efficient bipolar electrochemistry can be performed on an electrically-floating macroscopic conductive substrate using a tool we call the Scanning Bipolar Cell (SBC). The operating principle for the SBC is that current follows the path of least resistance. A high ohmic potential drop can be generated in the electrolyte adjacent to the conductive substrate by using a moderate conductivity electrolyte with a microjet cell geometry, inducing localized charge transfer on the substrate beneath the microjet. The equal and opposite redox chemistry necessary for sustained bipolar electrochemistry is spread over the macroscopic far-field of the floating conductive substrate. We combine experiments and finite element simulations to demonstrate this system using reversible copper redox chemistry. Bipolar electrochemical coupling to the surface can be highly efficient in the SBC and is governed by the balance of interfacial charge transfer and solution ohmic resistances, as characterized by the Wagner number of the system. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: [email protected]. All rights reserved.