The John D. and Catherine T. MacArthur Foundation is one of the largest private foundations in the United States. Based in Chicago but supporting non-profit organizations that work in 60 countries, MacArthur has awarded more than US$4 billion since its inception in 1978. With an endowment over $5.7 billion, the foundation provides approximately $230 million annually in grants and low-interest loans.
In addition to selecting the MacArthur Fellows, also known as "genius grants", topics of interest to the foundation include international peace and security, conservation and sustainable development, population and reproductive health, human rights, international migration, community development, affordable housing, digital media and learning, juvenile justice, and public interest media, including public radio and independent documentary film. The Foundation also gives grants to more than 200 arts and cultural institutions in the Chicago area.