Concentrations of particulate organic carbon (POC) and dissolved organic carbon (DOC), which together comprise total organic carbon, were measured in a reconnaissance study at sampling sites in the Upper Klamath River, Lost River, and Klamath Straits Drain in 2013–16. In addition, data for total nitrogen and chlorophyll a were collected. Optical absorbance and fluorescence properties of dissolved organic matter (DOM), which contains DOC, also were analyzed. Excitation-Emission matrices (EEMs) were produced for each sample and full absorbance spectra. The EEMs were compiled and key data points and regions of the spectra were extracted from each site. Parallel factor analysis was used to decompose the optical fluorescence data into five key components for all samples.