The Yellowstone Plateau Volcanic field consists of lavas from the last two million years. The most recent volcanic units are the Central Plateau Member and the older Upper Basin Member rhyolites (Christiansen, 2001). Investigations into the elemental and isotopic composition of these lavas can provide insight into the recent volcanic history of the different eruptive episodes and provide constraints on the hydrothermal fluid compositions that result from water-rock interactions occurring at depth within the hydrothermal system. In this Data Release, twenty-one samples of Yellowstone rhyolite samples from Upper Basin and Central Plateau Member lava flows were analyzed for major and trace element compositions via x-ray fluorescence (XRF). Analyzed samples include recently collected samples along with samples from the rock collection of Robert L. Christiansen (Robinson and others, 2021). This data was collected to constrain models of fluid-rock interaction of Yellowstone’s hydrothermal system. Christiansen, R.L., 2001, The Quaternary and Pliocene Yellowstone Plateau Volcanic Field of Wyoming, Idaho, and Montana. U.S. Geological Survey Professional Paper 729-G, 120 p. Robinson, J.E., McConville, E.G., Szymanski, M.E., and Christiansen, R.L., 2021, Yellowstone Sample Collection - database: U.S. Geological Survey data release, https://doi.org/10.5066/P94JTACV