The National Association of Social Workers (NASW) is the largest membership association of professional social workers in the world with nearly 145,000 members. Formed in 1955 by uniting seven predecessor organizations, NASW has a dual mission of protecting and advancing the profession of social work and of advocating for social justice issues. The NASW national office is based in Washington, DC, with chapters in each state, Puerto Rico, Guam, and the Virgin Islands. There are also separate chapters in New York City and metropolitan Washington, DC, as well as an international chapter for U.S. social workers living abroad.