The development of vertical nanoelectronics is hindered by limited control over the growth of nanostructures in specific directions. A scanning tunneling microscopy tip was used as a guide to locally consolidate individual nanoparticles and grow metallic nanopillars with high aspect ratios. Consolidation from random agglomerates occurs through electromigration and diffusion in a temperature gradient. The results of this study provide a new avenue for the controlled growth of complex metallic nanostructures for future three-dimensional architectures.