Cosmological and astrophysical measurements provide clear evidence for the existence of dark matter, and in recent years they have started to map dark matter over large volumes of the cosmos. At the same time, we still do not know much about the interaction properties of the dark matter particle(s?), and the possible mass of the particle could still space nearly 90 orders of magnitude. I will discuss some of the most promising probes of dark matter using small-scale cosmic structure, including dwarf galaxies, gravitational lenses, and the properties of stellar streams, and describe how these observations are starting to provide insight into the microphysical properties of the dark matter particle itself. Large photometric and spectroscopic surveys coming online this decade will accelerate this search, in a way that is complementary to other dark matter probes.