Unión de San Antonio is a town and municipality situated in the Mexican state of Jalisco. It is located approximately 32 km (20 mi) west of León, Guanajuato. The settlement was named in honor of Saint Anthony of Padua, as the first church constructed in the area was dedicated to him.
The primary local industry in Unión de San Antonio is agriculture. Key agricultural products include maize, wheat, and beans, alongside livestock production. As of 2005, the municipality had a recorded population of 15,484 residents.