The Chesapeake Monitoring Cooperative connects initiatives across monitoring groups and regions in order to amplify voices and enhance our understanding of the health of the Chesapeake Bay watershed. To accomplish this, we provide technical, programmatic, and outreach support in order to integrate volunteer-based water quality and macroinvertebrate monitoring data into a centralized data hub, the Chesapeake Data Explorer. These data are publicly available and used to assess the health of the Chesapeake Bay and watershed.