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© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hofig, D., Zhang, Y. G., Giosan, L., Leng, Q., Liang, J., Wu, M., Miller, B., & Yang, H. Annually resolved sediments in the classic Clarkia lacustrine deposits (Idaho, USA) during the middle Miocene Climate Optimum. Geology, 49(8), (2021): 916–920, https://doi.org/10.1130/G48901.1., The world-renowned Miocene Clarkia paleolake in northern Idaho (USA) is closely associated with Columbia River Basalt Group volcanism. The flood basalt dammed a local drainage system to form the paleolake, which preserved a plant fossil Lagerstätte in its deposits. However, the precise age and temporal duration of the lake remain unsettled. We present the first unequivocal U-Pb zircon ages from interbedded volcanic ashes at the P-33 type location, constraining the deposition to 15.78 ± 0.039 Ma. Using micro–X-ray fluorescence and petrographic and spectral analyses, we establish the annual characteristics of laminations throughout the stratigraphic profile using the distribution of elemental ratios, mineral assemblages, and grain-size structures, as well as organic and fossil contents. Consequently, the ~7.5-m-thick varved deposit at the type location P-33 represents ~840 yr of deposition, coincident with the end of the main phase of Columbia River Basalt Group eruptions during the Miocene Climate Optimum. The timing and temporal resolution of the deposit offer a unique opportunity to study climate change in unprecedented detail during global warming associated with carbon-cycle perturbations., This research was supported by U.S. National Science Foundation (NSF) grants EAR-1806015 to Zhang and EAR-1804511 to Yang and Leng. Zircon U-Pb analyses were made possible by the NSF-Major Research Instrumentation grant OCE-1626244 and the Texas A&M Research Development Fund award to Miller. We are grateful to the Kienbaum family for providing access to their private property to sample the P-33 site, and to Kunguang Yang from China University of Geosciences at Wuhan for the LA-ICP-MS analysis.