Oaks are keystone species across the majority of forest and shrubland habitats in the United States, but many are threatened with extinction in the wild. Ongoing conservation efforts exist for some native U.S. oak species, but growing threats and limited resources necessitate prioritization and coordination. To that end, The Morton Arboretum, BGCI-US, and the U.S. Forest Service conducted a conservation gap analysis of native U.S. oaks. As part of the analysis, we completed an extensive global ex situ survey, which enabled us to estimate the genetic and ecological coverage of ex situ collections for at-risk native oaks. These results facilitate the prioritization of species, populations, and regions for further representation in ex situ collections. Such analyses also pave the way for coordination among collections and provide a model approach for assessing other genera and regions.