San Jacinto Day is a significant holiday that is celebrated every year in the United States, specifically in Texas, on or around April 21st. The day has been commemorated since the Battle of San Jacinto on April 21, 1836, which marked a pivotal point for Texas during its revolution against Mexico. On this day, the Mexican army was caught unprepared and was defeated by the Texian Army led by General Sam Houston, bridging the path to Texas' independence.

The holiday is a state holiday in Texas and is observed by many across the state with various ceremonies, parades, speeches, and festivals. Some traditional activities include reenactments of the famous Battle of San Jacinto, picnics with friends and family, and various historical presentations. Several local schools and businesses close down to honor San Jacinto Day and the ethos of Texan independence.

On San Jacinto Day, it's typical to see the Texan flag flown across the state in homes, public institutions, and establishments. One particularly famous tradition is the annual 'Battle of Flowers' parade held in San Antonio. Commemorating the warriors of Alamo and San Jacinto, it's recognized as the first event to be part of the Texas Fiesta celebration. Though it's noted as a day of remembrance, it's also a day to celebrate Texan culture and identity, paying homage to the individuals who fought for the autonomy Texas enjoys today.