Rancho Tía Juana, or Ti Juan was a land grant made to Santiago Arguello on March 4, 1829, by Governor José María de Echeandía. It covered 26,019.53 acres in what is now Tijuana in the Tijuana Municipality of Baja California, Mexico and parts of San Ysidro and the Tijuana River Valley, San Diego in South San Diego in San Diego County, California.