I was told a trivia question once in which the teller did not have the
answer.  I have been dying to find out the answer.

The question is: There are 5 Official US Flags that never go to
half-staff.  What are they?  An obvious one is the one on the moon
(might be multiple ones) and possibly one at the bottom of the ocean
somewhere.  But the one I am most interested in is the one at the
Marine Corps Memorial (Iwo Jima) and if it goes to half-staff.

Thanks.

Hello and thank you for such an interesting question.

I located a number of different observations on where the US Flag is
never lowered to half staff. Everyone agress that on the moon and in
battle the American flag is never flown at half-staff.

In addition, flags hung vertically or horizontally against a wall or
building cannot be displayed at half-staff.

The following are the different views on where the U.S. flag is never
flown at half-staff.

According to the “Hear in Town” American Trivia Website, the following
are the U.S. flags that are never flown at half-staff:
 
- Arlington National Cemetery 
- The USS Arizona Memorial at Pearl Harbor 
- The Betsy Ross House 
- The Alamo 
- The moon 

Source: Here in Town American Trivia
http://www.hereintown.com/trivia.htm#Halfstaff

The Jim Zaleta Trivia Question addresses your inquiry for the Marine
Corp Memorial Flag:

There are only two American flags that are never flown at half staff.
  
- The flag on the Iwo Jima Marine Memorial in Arlington, VA.
- The flag on the lunar surface

Source: Jim Zaleta Trivia Question
http://www.geocities.com/jimzaleta/Flags.html

At Peterson Flags Website it is mentioned that the U.S. flag is never
flown at half-staff in:

- battle
- moon

Source: Peterson Flags
http://www.petersonflags.com/flaginfo.htm

At Google Newsgroups they were asking the same question in May 2000.

“Name the five locations where the flag is flown constantly, and
never lowered to half staff.”

1. Tranquility Base, Luna
2. In Battle

“Some places where it's flown 24 hours a day by law or presidential
proclamation, but I don't know if it's lowered to half staff:”

- Fort McHenry National Monument and Historic Shrine
- Flag House Square, Albemarle and Pratt Streets, Baltimore Maryland
- United States Marine Corp Memorial (Iwo Jima), Arlington, Virginia
- Lexington Green, Town of Lexington, Massachusetts
- The White House, Washington, DC.
- United States Customs Ports of Entry which are continually open.
- Grounds of the National Memorial Arch in Valley Forge State Park,

Source:Google Newsgroups
http://groups.google.com/groups?q=flag+never+flown+at+Half-staff&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=8fumgt%24l9t%241%40nnrp1.deja.com&rnum=13

At USA Flags frequently asked questions:

“The only flags that can not be displayed at 'half-staff' are those
hung vertically or horizontally against a wall or building.”

Here are the Presidential proclamations and laws since that time
authorize the display of the flag 24 hours a day at the following
places:

- Fort McHenry National Monument and Historic Shrine, Baltimore,
Maryland (Presidential Proclamation No.2795, July 2, 1948).

- Flag House Square, Albemarle and Pratt Streets, Baltimore Maryland
(Public Law 83-319, approved March 26, 1954).

- United States Marine Corp Memorial (Iwo Jima), Arlington, Virginia
(Presidential Proclamation No.3418, June 12, 1961).

- On the Green of the Town of Lexington, Massachusetts (Public Law
89-335, approved November 8, 1965).

- The White House, Washington, DC. (Presidential Proclamation No.4000,
September 4.1970). Washington Monument, Washington, DC. (Presidential
Proclamation No.4064, July 6,1971, effective July 4, 1971). Fifty
flags of the United States are displayed at the Washington Monument
continuously.

- United States Customs Ports of Entry which are continually open
(Presidential Proclamation No.4131, May 5, 1972).

- Grounds of the National Memorial Arch in Valley Forge State Park,
Valley Forge, Pennsylvania (Public Law 94-53, approved July 4, 1975).
http://www.geocities.com/flag_of_usa/frequently_asked_questions.htm

According to the Farmers Almanac:

 “The flag must be flown at half-staff on all buildings on the death
of any officer listed below, for the period indicated:

- President or a former President: 30 days from the date of death. 

- Vice President, the Chief Justice or a retired Chief Justice of the
United States, or the Speaker of the House of Representatives: 10 days
from the day of death.

- Associate Justice of the Supreme Court, a member of the Cabinet, a
former Vice President, the President pro tempore of the Senate, the
Majority Leader of the House of Representatives, the Minority Leader
of the House of Representatives: From the day of death until
interment.

-  United States Senator, Representative, Delegate, or the Resident
Commissioner from the Commonwealth of Puerto Rico: the flag should be
flown in the metropolitan area of the District of Columbia, on the day
of death and on the following day; in the state, congressional
district, territory, or commonwealth of such Senator, Representative,
Delegate, or Commissioner, from the day of death until interment.

- Governor: Within the state, territory, or possession, from the day
of death until interment.

Source: Farmers Almanac
http://www.almanac.com/edpicks/flag.html


Search Criteria:

flag half-staff trivia
"US flag never flown at Half-staff"
“half-staff” at Iwo Jima Memorial 

I hope this helps.

Best Regards,
Bobbie7-ga

Very fast.  Great amount of added information.