Regional accreditation is the educational accreditation of schools, colleges, and universities in the United States by one of six regional accrediting agencies. Accreditation, technically a voluntary process, is a means by which colleges demonstrate to each other, and sometimes to employers and licensing agencies, that their credits and degrees meet minimum standards. It is the self-regulation of the higher education industry.
Each regional accreditor oversees the vast majority of public and private educational institutions, both not-for-profit and for-profit, in its region. Their primary function is accreditation of post-secondary institutions, though there is a limited amount of accreditation of primary and secondary schools.
While it might seem that national accreditation would be more important than regional accreditation, this is, in general, not the case. Regional accreditation is much older, and (with a few exceptions) more rigorous and prestigious than national accreditation. Most non-profit institutions are regionally, not nationally, accredited. National accreditation is legitimate in some specific subject areas, such as nursing or car repair.