The Marine Corps Blood Stripe
Every Marine hears it at boot camp: the scarlet stripe on the dress blue trouser leg honors the blood spilled storming Chapultepec in 1847. The Marine Corps' own museum says that story has no basis.
How it actually works
Officers and staff NCOs/NCOs wear a scarlet trouser stripe on their dress blues — two inches wide for general officers, one and a half inches for other officers, and just over an inch for staff NCOs and NCOs. The stripe dates to a January 1840 order, itself following a broader 1837 uniform overhaul under President Andrew Jackson that had the Marine Corps adopt the Army's practice of trouser stripes matching the uniform jacket's facing color.
The legend told to every recruit is that the stripe commemorates Marine blood spilled taking Chapultepec Castle during the Mexican-American War in 1847. The Marine Corps University museum addressed this directly in a piece titled "The Blood Stripe Myth": the trouser stripe was adopted in 1837-1840, a full decade before Chapultepec, so the timeline does not work. The casualty count undercuts the legend further — seven Marines were killed at Chapultepec out of a landing force of roughly 400 to 450, a real and honored sacrifice, but not the scale the origin story implies. The stripe is real, the honor it represents is real; the specific battle story attached to it is folklore that outlived the official correction.
Adopted from U.S. Army uniform regulations, 1837-1840, predating the 1847 Battle of Chapultepec by roughly a decade.