Due to a historical paucity of collections from and the absence of a comprehensive floristic treatment for parts of the Caribou-Targhee National Forest and Curlew National Grassland, an updated inventory for the area was needed. I present an annotated checklist of the vascular plants documented from the Caribou-Targhee National Forest and Curlew National Grassland. A total of new 3189 voucher specimens were collected for this project in 2021 and 2022. To compile the annotated checklist, I consulted both newly collected specimens and specimen data from online botanical databases. A total of 1557 taxa (species, subspecies, varieties, and hybrids), 1423 species (including hybrids), 481 genera, and 94 families are known to occur in the study area. At least three new state records (Draba thompsonii (C.L. Hitchc.) G. Mulligan & Al-Shehbaz, Sphaeralca parvifolia A. Nelson, and Boechera lasiocarpa (Rollins) Dorn) and 137 new county records were documented, a few of which were published previously. An additional 38 first records were discovered, of which approximately 21.1% were not native to the United States. A number of other important occurrences were documented, such as occurrences of rare taxa, Forest Service Region 4 Sensitive Species, and new reports of non-native taxa. The large number of documented county records supports the continued applicability of the Wallacean Shortfall in the flora of western North America. Employees of the U.S. Forest Service, academic researchers, and others will be able to use the annotated checklist to better understand, research, and conserve the flora of the Caribou-Targhee National Forest and Curlew National Grassland