When did the Republic of Texas join the United States ?
- 8 years agoFavorite Answer
Texas became our 28th state in December 28, 1845.Source(s): Author of Book on Sam Houston
- 8 years ago
Texas was annexed during the Mexican American War...I think that was the name of the war, but I remember learning about Santa Anna (ruler of Mexico at the time, which was before the Civil War) having conflicts with the United States. Texas declared independence and we annexed it later.