Network distribution center

A network distribution center (NDC) was a highly mechanized mail processing plant of the United States Postal Service that distributed standard mail and package services in piece and bulk form. The NDC network was dismantled in 2022-2023 by the USPS as part of Postmaster General Louis DeJoy’s Delivering for America network rationalization plan, which saw mail classes formerly handled by the NDC network merged into mailstreams in processing and distribution centers. Each former NDC, all of which were located in buildings owned by USPS, are implementing or in the process of creating individual plans for repurposing the buildings. Many are being restacked into RPDC s, which will form the backbone of the new USPS network, whereas others are being used to insource previously outsourced transportation functions such as surface transfer centers (STCs), or terminal handing services (THS), which handled airmail, in addition to continuing to support processing and distribution centers with the handing of priority and ground advantage parcels.

List of network distribution centers
The United States Postal Service had 21 NDCs:

For mail originating in ZIP Code Areas 006-009 and addressed to addresses in those ZIP Code Areas, the sectional center facility in San Juan, Puerto Rico serves as the NDC.

List of international service centers
The United States Postal Service also has 4 international service centers (ISC) for distributing international mail:

In addition to the four ISCs, the postal service has four International Exchange Offices (IEOs), which are authorized to accept and process limited inbound and outbound international mail volumes. IEOs handle less than 5% of international volume, and do not have the full capabilities and functions of ISCs. Currently, the postal service has four active IEOs: The New Jersey Network Distribution Center in Jersey City, NJ, the Honolulu Processing and Distribution Center in Honolulu, HI, the Pago Pago Main Post Office in Pago Pago, American Samoa, and the Barrigada Post Office in Barrigada, Guam.