Abstract This field trip is tied to a GSA 2016 joint Pardee Keynote Symposium (P5) and related topical session on the Cenozoic geology of the Great Plains (T201) that integrate new breakthroughs in scientific coring and sedimentary geoscience with the long-term demand for better characterization of the High Plains aquifer. The aquifer is the primary source of groundwater for all uses on the Great Plains, and is experiencing historic declines in water levels that could seriously compromise sustainability in areas under increasing developmental stress. Understanding the depositional history, stratigraphic framework, and hydrogeologic properties of the Cenozoic sediments comprising the aquifer is important for developing water management strategies. This guide describes a three-day field trip to examine several ongoing and increasingly collaborative projects investigating the depositional history, stratigraphy, and paleoecology of the Cenozoic High Plains. The field trip is focused on two main areas: (1) the Denver Basin, where synorogenic sedimentation associated with the Laramide orogeny deposited sediments during the late Eocene; and (2) the High Plains of western Kansas, where during the Miocene–Pliocene uplift of the Rocky Mountains, a series of clastic wedges prograding eastward formed a nearly contiguous aggradational surface covering most of the western Great Plains. Late Cenozoic uplift of the region initiated deep incision into Neogene strata and the subsequent exposure of sediments and paleosols of the Ogallala Formation. During the trip, we will visit sites and landscapes that have a long and rich history of geologic investigation. In addition to previously published results, we also present new data on the sedimentology, geochronology, paleontology, and paleoichnology of Cenozoic High Plains deposits.