In-situ atomic force microscopy (AFM) is used to enhance Cu electrodeposition on Cu and Au single crystal electrodes. On Cu surfaces, the enhanced deposition effect depends primarily on tip-sample force, crystallographic orientation, and solution pH. Enhanced Cu deposition is stronger on the (110) face of Cu than the (111) face which correlates with the reactivity of these lattices toward oxygen adlayer formation. For a specific orientation, enhanced Cu deposition becomes less pronounced with decreasing solution pH. These results are consistent with a modification mechanism in which partially passivating oxygen adlayers mediate both normal and enhanced Cu deposition. The AFM tip-sample force physically creates defects in these adlayers, thus forming active sites for Cu adsorption. The general applicability of this scheme is demonstrated on Au(111) passivated with self-assembled octadecanethiol monolayers.