Regional Accrediting Associations accredit institutions that are located within defined groups of states and territories, as well as foreign institutions located in specified countries and world regions which apply for U.S. accreditation. While regional associations inspect and approve all types of institutions, they particularly serve traditional institutions that offer degree programs in a comprehensive range of academic subjects, such as universities and colleges. There are 6 regional accrediting associations.

National Accrediting Associations accredit institutions located anywhere within the United States or overseas. They concentrate on providing accreditation to institutions offering degree programs in a narrow range of related specialized subjects, or using nontraditional modes of delivery, rather than to comprehensive liberal arts institutions.

Professional or Specialized Accrediting Associations accredit specific programs of study offered within, and by, institutions that are regionally or nationally accredited. Professional/specialized associations do not accredit entire institutions except in a few cases where an institution offers only one degree program in a single subject, and thus accreditation of the program is equivalent to accreditation of the institution.
Definitions:

Specialized and Professional provides the definition of specialized and professional accrediting used by the Association of Specialized and Professional Accreditors (ASPA).

Accrediting associations of the types listed above accredit all levels of education. Most primary and secondary schools are accredited by regional or national associations because U.S. education at these levels tends to be unspecialized.