https://tshaonline.org/handbook/online/articles/lkj01
JUNETEENTH. On June 19 ("Juneteenth"), 1865, Union general Gordon Granger arrived in Galveston and issued General Order Number 3, which read, "The people of Texas are informed that, in accordance with a proclamation from the Executive of the United States, all slaves are free.
https://en.wikipedia.org/wiki/Juneteenth
Juneteenth, also known as Juneteenth Independence Day or Freedom Day, is an American holiday that commemorates the June 19, 1865, announcement of the abolition of slavery in the U.S. state of Texas, and more generally the emancipation of enslaved African Americans throughout the former Confederate States of America. Its name is a portmanteau of "June" and "nineteenth", the date of its celebration.[1][2] Juneteenth is recognized as a state holiday or special day of observance in forty-five states.[3]
Today it is observed primarily in local celebrations. Traditions include public readings of the Emancipation Proclamation, singing traditional songs such as "Swing Low, Sweet Chariot" and "Lift Every Voice and Sing", and reading of works by noted African-American writers such as Ralph Ellison and Maya Angelou.[4] Celebrations may include rodeos, street fairs, cookouts, family reunions, park parties, historical reenactments, or Miss Juneteenth contests.[5] The Mascogos, descendants of Black Seminoles, of Coahuila, Mexico also celebrate Juneteenth.[6]