The Sacatar Trail Wilderness (STW) occupies a unique ecological transition zone in the southeastern Sierra Nevada at the interface of the Mojave Desert, Great Basin Floristic Province, and highly diverse California Floristic Province. This 88mi2 area encompasses a significant elevational gradient from 3,500 to nearly 9,000 feet, and supports a diverse array of vegetation communities, from creosote scrub to montane meadows. The absence of weather stations within the STW make it difficult to understand the precise microclimates its plants are subject to, especially considering that conditions vary within such a wide elevational range. This region of the Sierra Nevada on the western edge of the Mojave Desert, if more thoroughly studied, could potentially serve as a setting for future research on plant migration in response to climate change. The STW is also a “botanical black-hole,” an area with little to no documentation of the plants that occur there. The most notable collector in the area was botanist Ernest C. Twisselmann, who made 36 collections from 1958 to 1971. The STW’s habitat heterogeneity coupled with insufficient documentation suggests possibilities for discovering new rare plant occurrences and potentially undescribed diversity. Research objectives are (1) to produce a comprehensive inventory and annotated species checklist to document all vascular plants within the STW, (2) to generate more precise weather data from the site, and (3) to characterize the vegetation communities through quantitative surveys.  Thirteen trips were made to the study site between March and September 2022, with an estimated fifteen additional trips anticipated for 2023 to voucher specimens of all vascular plant taxa present. To supplement the limited climate information available for the STW, 12 iButton temperature data loggers have been installed along the study site’s elevational gradient at 1,000-foot intervals. The data logging points will be further analyzed with 10-meter radius plots to characterize vegetation types in conjunction with elevation. Historic collections from the site will be examined and identifications verified. All collections data, including those from historic collections, will be assimilated into an annotated species checklist. Specimen vouchers collected as part of this research will be deposited in RSA, UCR, and CAS herbaria and corresponding data shared with the Consortium of California Herbaria (CCH2) database portal.  During the first field season 827 collections were made, representing 67 plant families. Range extensions were documented, including the southernmost record of yellow-flowered wild buckwheat (Eriogonum microtheca var. ambiguum), and the first ever record of California milkweed (Asclepias californica) in Inyo County. New occurrences of several rare taxa have been located, including Charlotte’s phacelia (Phacelia nashiana) and Kern bird’s beak (Cordylanthus eremicus subsp. kernensis), both of which the California Native Plant Society classify as rank 1B threatened taxa. Aside from exciting plant observations, this area is inhabited by the rare and threatened Mojave desert tortoise at the very northwest reaches of its range. Preliminary findings from this research demonstrate the unique and ecologically important value of this area.