This dissertation examines an enormously influential organization that gave shape to normative American assumptions about the relationship between gender, race, citizenship, and the environment in the early twentieth century. The Boy Scouts of America [BSA] garnered a broad range of popular and government support for promising to teach a universal model of character and leading citizenship to all boys. However, many officials doubted that non-white, working class immigrant, and rural boys were capable of such training. Administrators justified allowing local councils to discriminate against "undesirable" groups as permitting "self-determination" in local matters. This research revises one of the central tenets of Progressive Era gender history. A number of works incorrectly use Scouting as the key proof for a flawed argument that native-born white, middle class men's ideal of manhood shifted to a virile self-reliance that idealized "primitive" non-white races. Virile primitivism, however much it may have shaped men's fantasies, was of little practical use in an urban-industrial society. The BSA actually garnered support from across the socio-economic spectrum for its articulation of a new vision of balanced, "modest manliness." Scout manliness hedged pioneer-like virility with Victorian self-control and the expert management, scientific efficiency, and hierarchical loyalty that native-born white, middle class men needed to adapt to the corporate industrial workforce and to reinforce their dominant position in an urbanizing social hierarchy. Girls and non-white boys worked to overcome their obstacles to participation in Scouting. Environmental historians studying the early twentieth century have emphasized the battle over public land usage between utilitarian natural resource conservationists and pristine wilderness preservationists. Attention to the BSA points to the power and popularity of a third vision. BSA leaders insisted that forests should be set aside because they were rich with masculine history and provided an arena for reordering an increasingly diverse, feminized society. Natural resource conservation taught boys modern virtues like expert management and scientific efficiency. BSA officials encouraged members, as future leaders, to apply conservation's categorization of species based on productivity to the differential treatment of human groups based on character capacity. Scouts learned to manage human resources by conserving natural resources.