​The Clustered Mail Delivery is a service which provides mail delivery and collection from a cluster of mailboxes centrally located in an area of a building; and the customer controls the distribution of mail. This type of service is more economical and efficient than the door-to-door mail service.

This service is implemented in all new buildings constructed on the NIH campus and in newly leased facilities off-campus where NIH employees are the sole occupants. Door-to-door mail service that is currently provided to some NIH offices will be phased out and eventually replaced by the Clustered Mail Delivery Mail Service.