Santa is a 4th class municipality located in the central coast of Ilocos Sur Province. It is bounded on the north
by Caoayan and Bantay, on the east by Abra Province, on the south by Natvacan, and on the west by South China Sea.
It has a total land area of 109 square kilometers and is politically subdivided into 26 barangays.
The town is situated 366 kilometers north of Manila and 41 kilometers south of Vigan City, the provincial capital.