USA Flag Red Blood Red Deep blood Flag Red is the color of blood shed during the struggle for independence of the colonies from the The British Crown. Flag Red signifies the valor of those who made the ultimate sacrifice in the Revolutionary War of the late 1700's to free those states that are now the USA. Use Flag Red when customizing items for any graduation, 4th of July festivities or celebratory event, including birthdays, anniversaries, weddings and engagements.