America’s national accreditation body is ANAB. They assess and accredit certification bodies that audit and certify organizations conforming to management system standards.
ANAB accreditation covers many industries – from information security and telecommunications, to aerospace and food safety. They offer accreditation to a number of standards, including ISO27001 and ISO9001.
If you have been approached by a certification body in your state, use ANAB’s directory to confirm that they have a valid ANAB accreditation certificate.
http://anabdirectory.remoteauditor.com/
It is important to note that organizations should not feel restricted to use only those certification bodies listed in this search engine; in fact, any certification body accredited by a national accreditation body subscribing to the IAF can offer accredited certification to companies in the USA and many do, subject to their accreditation schedule.