Shaped colloids can be used as nanoscale building blocks for the construction of composite, functional materials that are completely assembled from the bottom up. Assemblies of noble metal nanostructures have unique optical properties that depend on key structural features requiring precise control of both position and connectivity spanning nanometer to micrometer length scales. Identifying and optimizing structures that strongly couple to light is important for understanding the behavior of surface plasmons in small nanoparticle clusters, and can result in highly sensitive chemical and biochemical sensors using surface-enhanced Raman spectroscopy (SERS). We use experiment and simulation to examine the local surface plasmon resonances of different arrangements of Ag polyhedral clusters. High-resolution transmission electron microscopy shows that monodisperse, atomically smooth Ag polyhedra can selfassemble into uniform interparticle gaps that result in reproducible SERS enhancement factors from assembly to assembly. We introduce a large-scale, gravity-driven assembly method that can generate arbitrary nanoparticle clusters based on the size and shape of a patterned template. These templates enable the systematic examination of different cluster arrangements and provide a means of constructing scalable and reliable SERS sensors.nanocrystal | self-assembly | plasmonics | nanopatterning T he ability to control the arbitrary position, orientation, and connectivity of colloidal building blocks with nanoscale precision is an objective of materials research that is critical for advances in fields including electronics, energy harvesting/conversion, optics, and biosensing (1-4). Additionally, many barriers in our understanding of fundamental nanoscale phenomena are frequently overcome by ever more precise tools to manipulate the processes and organization of matter across extended and multiple-length scales (5, 6). The impact of new tools is particularly apparent in the field of plasmonics, which uses the collective excitations of free electrons in nanoscale metallic structures and periodically structured composites to control and manipulate light at deeply subwavelength scales (7-9). Experiment and simulation show that the subtle differences in the size, geometry, and spacing of metal nanostructures strongly impact their optical properties (10-13). However, to accurately and reproducibly fabricate structures using top-down tools is limited by the challenge of controlling nanoscale materials dimensions that depend on the crystallinity and surface roughness of materials (14-16).Noble metal nanoparticles can be synthesized in a variety of shapes with exceptional monodispersity (17, 18) and self-assembled into complex, ordered structures (19-21). The outcome of the assembly process depends on particle shape, size, relevant particle interactions, and external driving forces (22). Because their surfaces are atomically smooth, polyhedral nanocrystals can form interparticle gaps with distinct, flat interfaces that are below 2 ...