Santiago is both a Spanish and Portuguese[2] surname.
The surname Santiago was first found in Galicia, Spain.
There are other forms that are shortened versions of Santiago: Sant, Santo, Sancto, Sancti, Sanct, Sanctis Santi.
Also, these spellings apply to all the righteous men of the Calendar of the days of the Patron Saints.
[3] Santiago is a habitational name from any of the numerous places named for the dedication of churches to St. James (Sant Iago).