Nonprofit organizations in the United States play a vital role delivering services, strengthening communities, and facilitating civic engagement. In our nationally representative survey of nonprofit organizations fielded January through April of 2021, we focus on operating 501(c)(3) public charities whose activities range from direct service provision to community building and advocacy. We provide new evidence about the nonprofit sector in three ways. First, our nationally representative survey provides important data on geographic and demographic characteristics of the people and communities that nonprofits serve across the United States and the demographic diversity and representation of organizations’ staff and leadership. Second, our study shows how organizations of different sizes and in different subsectors and geographic contexts have been affected by recent trends in donations and how they were affected by the events of 2020. Third, recognizing that the trends we discuss are constantly changing, our study is an ongoing panel study, and future surveys will analyze longitudinal trends in organizational characteristics and donations. We also provide a public use dataset of most of the survey data we collected so that others across the country can investigate questions of their own. Please see our project page for more information about our long-term study plans.