San Diego De Alejandria

Andres Fonseca and Petra Rodrigues had several children born in San Diego De Alejandria between 1819 and 1831 and maybe earlier although those records are missing. Andres' parents were Rafael Fonseca and Maria Antonia Santos. Does anyone know the probable travel route or city of origin of early San Diego De Alejandria families? Thanks. I would appreciate any assistance. Evie Villegas