Club Atlético Unión, commonly known as Unión de Santa Fe, is a historic Argentine football club based in the city of Santa Fe, competing in the Argentine Primera División. The club plays its home matches at the iconic Estadio 15 de Abril, known for its passionate and intimidating atmosphere. Founded in the early 20th century by a group of railway workers, the club's name and red-and-white colors reflect its working-class roots. Unión has experienced periods of great success, including a memorable Copa Sudamericana campaign and strong finishes in the domestic league. While they have not won the top-tier league title, they are known as "El Tatengue" and have a fierce rivalry with fellow Santa Fe club Colón. In the modern era, Unión consistently aims to solidify its place in the top flight, often relying on a strong team spirit and a formidable home record. Their fan base is famously loyal and vocal.