The U.S. Service Flags Grouping contains samples of various service flags introduced during the First World War to designate family members serving in the US Armed Forces. They were and remain an official flag of the US Government, whose use and display, although widespread and largely arbitrary, were actually controlled by the Secretary of the Army (now the Secretary of Defense), who was tasked with overseeing their design, construction and manufacture. Service Flags were generally used to bolster morale on the home front. If a member of the family was killed, the star that was representative of the deceased loved one would be changed to gold.

Significant flags in this grouping are one institutional flag which displays 943 servicemen. Also unusual are two service pennants which identified to specific soldiers and the U.S. Army service corps in which they served.

Also included are several versions of the flag created as jewelry for civilian wear and a rare Service Star flag booklet explaining the practice.