The United Nations Postal Administration (UNPA) is the postal agency

Mail

Mail, or post, is a system for transporting letters and other tangible objects: written documents, typically enclosed in envelopes, and also small packages are delivered to destinations around the world. Anything sent through the postal system is called mail or post.In principle, a postal service...

 of the United Nations

United Nations

The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

. It issues postage stamp

Postage stamp

A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

s and postal stationery

Postal stationery

A piece of postal stationery is a stationery item, such as a stamped envelope, letter sheet, postal card, lettercard, aerogram or wrapper, with an imprinted stamp or inscription indicating that a specific rate of postage or related service has been prepaid...

, denominated

Denomination (postage stamp)

:This article deals with the price of a postage stamp. For other meanings of the word 'denomination' see Denomination .In philately, the denomination is the "inscribed value of a stamp"...

 in United States dollar

United States dollar

The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

s for the United Nations offices in New York

New York City

New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

, in Swiss francs for the offices in Geneva

Geneva

Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...

 and in euros (formerly schillings) for the offices in Vienna

Vienna

Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

. Postage rates charged are identical to those of the host nation.
Only United Nations stamps in the appropriate currency may be used at a given United Nations office.