Final answer:
Three national U.S. holidays are Independence Day, Thanksgiving, and Memorial Day.
Step-by-step explanation:
Three national holidays in the U.S. are Independence Day, which celebrates the country's independence from Great Britain on July 4th; Thanksgiving, a holiday where people gather to give thanks for the blessings of the year and is celebrated on the fourth Thursday in November; and Memorial Day, a day honoring and remembering the men and women who have died in military service, observed on the last Monday in May.
Learn more about U.S. national holidays