•	The hierarchical elements, or containers, of Active Directory include forests, trees, domains, organizational units (OUs), and sites
•	Forests
o	Highest level in an Active Directory consists of one or more trees that are in a common relationship.
•	Tree
o	Contains one or more domains that are in a common relationship
•	Domain
o	A logical partition within an Active Directory forest in which to house objects that have a common relationship.