Creating and Managing Organizational Units (OUs)
Organizational units (OUs) are logical administrative units that can help you limit the scope of a domain. They can contain many types of objects, including those for computers, contacts, groups, printers, or users. Because they can also contain other OUs, you can build a hierarchy of OUs within a domain. You can also use OUs to delegate administrator privileges on a limited basis.
Creating an OU
You can create OUs in Active Directory Users And Computers. As long as you use an account that is a member of the Administrators group, you'll be able to create OUs anywhere in the domain. The only exception is that you cannot create OUs within the default containers created by Active Directory.
Note that ...