Between 2018 and 2023, eighteen regional historical societies, community organizations, and native nations collaboratively co-curated Calumet Voices, National Stories, a traveling exhibition telling the environmental, industrial, and social history of the Calumet region from southeast Chicago to northwest Indiana. The Field Museum in Chicago served as a key partner, and the project has been praised both for focusing attention on the region and for its collaborative curation model. I examine how a large natural history museum came to share authority with unconventional partners, contextualizing the networks that created Calumet Voices within longer institutional and intellectual histories. The Field pivoted between strategies of community engagement, biodiversity conservation, local heritage, and exhibition development to engage with Chicagoland from the 1980s to the present. I trace how the museum built both capacity and motivation to bring Calumet Voices within the scope of its mission. As museums increasingly turn to these techniques to tell stories of environmental justice and diverse communities, Calumet Voices offers a case study to historicize collaborative curation.