Eleven Major Categories of U.S. Stamps


The stamp known as the “workhorse” of the postal system is the definitive, or regular-issue stamp. Paying postage on everyday mail, it’s issued in a wide variety of denominations. A single issue is used for long periods of time. Definitives are interesting to collect. Since their extended use means they are reprinted from time to time, there can be many differences among the stamps, which at first glance appear the same. You may find differences in design due to variations in printing plates, printing methods, color, margin dates, watermarks (on older US stamps), perforations, and type of gum (self-adhesive or water-activated).

Flag Stamps are a good example of Definitive stamps.


In 1893, a new type of stamp was introduced. The commemorative is a stamp issued to honor an important person, event, or anniversary. It’s printed in smaller quantities than definitives, and is sold for a limited time, usually a few months. Unsold stamps are generally destroyed. The first US commemorative stamps were issued to commemorate the 1893 World’s Columbian Exposition. The 16-stamp series depicted the various stages of Columbus’s voyages to the New World. Today these stamps are highly valued by collectors. Commemoratives make America’s history come alive.


Semipostals are postage stamps with an additional charge (called a surcharge) intended to raise money for a specific cause. In 1997, the Postal Service issued the first US semipostal stamp. It paid the 32¢ postage rate and an extra 8¢ from its sale went to help fund breast cancer search. In 2002 the Heroes of 9/11 semipostal raised funds for the families of emergency personnel killed or disabled in the September 11, 2001, attacks on America.

Scott numbers for semipostals begin with a “B”.


In 1918, Airmail Service was started in the US and there was a need for special stamps to pre-pay Airmail postal rates. The first Airmail stamp was the 24¢ Curtiss Jenny. US mail is routinely carried by air now. Because of that, the US Postal Service has stopped issuing Airmail stamps. Airmail stamps are listed with Scott numbers beginning with “C”.

From 1934-36, the Post Office Department issued Airmail Special Delivery stamps. These were to provide air postage and a fee for special delivery. There were only two such stamps issued: Scott numbers CE1 & CE2.

Postage Due

The first postage due stamp was issued in 1879. Its use indicated an amount due to the post office when not enough postage was put on a piece of mail. Postage due stamps have large numerals indicating the amount of postage owed. Use of postage due stamps was discontinued in 1986. Postage due stamps have Scott numbers beginning with “J”.

Special Delivery

In 1885, a new postal service was begun – special delivery. The special delivery stamp indicated that an extra fee had been charged for immediate delivery to a person’s address once the mail was delivered to the nearest post office. Special delivery stamps are designated by Scott numbers beginning with “E”.

Parcel Post

In 1912, stamps were introduced to pay postage on parcels. There were twelve parcel post stamps issued, all with different denominations and designs, but with the same format and color. Postal workers had trouble telling the difference between the 1¢ and $1 stamps. By 1913, parcel post charges could be paid for with any stamp, and parcel post stamps became obsolete. Scott numbers for parcel post stamps begin with “Q”.

Also issued in 1912 were the Parcel Post Postage Due stamps. They are Scott number “JQ” and show that there is an amount to be collected from the addressee.


The term “official” refers to a stamp used only by a department of the government. In 1873, the US issued official stamps for the Executive Branch and the departments of Agriculture, Interior, Justice, Navy, Post Office, Treasury, and War. These official stamps were in use for seven years. Now there is just one type of official stamp which is used by all branches of government. Scott numbers for officials begin with “O”.


The final major type of US stamp is the revenue stamp. These stamps show the collection of tax or payment of a fee. The most popular of these revenues are probably the migratory bird hunting stamps, or “duck stamps,” as they are commonly called. They are issued annually. Revenue stamps are given Scott numbers beginning with an “R”.

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