American-Related Subjects
While many non-American events and personalities have impacted the United States of America's history, they generally do not feature on U.S. postage stamps. Other countries may have different criteria, but the United States generally sticks to this guideline.
The USPS and CSAC consider events, people and themes that they deem to have extensive nationwide appeal and importance. Local postmasters may consider local/regional subjects for a stamp for collecting purposes or for special postal cancellations with a special postal mark that prevents a stamp's reuse.
If an event, person or theme has received stamp issuance within the last 50 years, the USPS and CSAC will not consider that subject for another commemoration. Exceptions to this rule include traditional themes such as holidays and national symbols.
The USPS and CSAC will not consider commemorating religious institutions or persons whose major accomplishments are tied to religious beliefs and works.
Individuals
The USPS and the CSAC only consider honoring deceased individuals on stamps. With the exception of U.S. presidents, the organizations do not consider subject proposals until at least two years following the subject's passing. Furthermore, any such stamp will not appear earlier than five years after the person's death. Deceased U.S. presidents remain the lone exception to the five-year rule; the USPS may issue a memorial stamp honoring the individual on his first birthday following his death.
The debut of a commemorative stamp (or postal stationery items) honoring all other individuals will usually coincide with an anniversary of the person's birth. For example, the USPS issued the Elvis Presley commemorative stamp on January 8, 1993, the 58th anniversary of Presley's birth.
Events
Events of historical importance must be at least 50 years old to be eligible for consideration for commemoration on a stamp. The USPS and CSAC consider such events in 50-year anniversary intervals. For example, if the organizations pass on commemorating an event's 100th anniversary, they will not consider it again for another 50 years.
Similarly, the USPS and CSAC consider requests for statehood anniversaries in 50-year intervals from the date the state first entered the Union. Other state-related or local/regional anniversaries also receive consideration in 50-year intervals, but only as subjects for postal stationery. Occasionally, the USPS and CSAC make exceptions; for example, 2009 stamps celebrated the 20th anniversary of "The Simpsons" animated TV series.
No matter the occasion, commemoration requests should reach the USPS and CSAC at least three years prior to the desired issue date to allow adequate time for consideration and, if selected, for the stamp's design and production.
Groups and Organizations
The USPS and CSAC do not consider commemoration of federal agencies, cities, counties, municipalities, towns, hospitals, libraries, and primary or secondary schools, simply because too many organizations of these types exist. However, they will consider Historic Preservation Series stamped card commemoration requests for universities and other higher education institutions. Such consideration would occur on the 200th anniversary of the institution's founding. Fraternal, political, sectarian, or charitable or service organizations are not eligible for commemoration, nor are individual commercial enterprises or products.