This robust 2023 report reviews the concept of belonging, centering its importance for key stakeholders, leaders, and philanthropists in the US today who care about health, democracy, and intergroup relations. The report introduces the Belonging Barometer, a way of measuring belonging that is robust, accessible, and readily deployable in the service of efforts to advance the common good. The Belonging Barometer was used in a nationally representative survey in late 2021 to assess the state of belonging in five life settings: family, friends, workplace, local community, and the nation. The report concludes with considerations for designing interventions that increase belonging.