Dataset for Chapter Trace Elements and their Isotopes in Streams and Rivers. A dataset listing all trace element concentrations used for figures in the Chapter. The occurrence and speciation of trace elements in streams and rivers are controlled by interconnected hydrogeological, biogeochemical, and anthropogenic factors that include rock weathering, climate, vegetation, and land use within the watershed. The purpose of this chapter is to provide a broad overview of trace element abundance, speciation, and mobility in streams and rivers. We also discuss how trace elements are mobilized into stream networks and transformed during transport. Select isotopic systems are reviewed in order to provide examples of how isotopic analyses can be used to understand geochemical and anthropogenic processes. The occurrence and speciation of trace elements in streams and rivers are controlled by interconnected hydrogeological, biogeochemical, and anthropogenic factors that include rock weathering, climate, vegetation, and land use within the watershed. The purpose of this chapter is to provide a broad overview of trace element abundance, speciation, and mobility in streams and rivers. We also discuss how trace elements are mobilized into stream networks and transformed during transport. Select isotopic systems are reviewed in order to provide examples of how isotopic analyses can be used to understand geochemical and anthropogenic processes.