The primary coordinate point for San Sebastian is located at latitude 18.3366 and longitude -66.9902 in San Sebastián Municipio.
The formal boundaries for the San Sebastián encompass a land area of 2.03 sq. miles and a water area of 0 sq. miles.
San Sebastián Municipio is in the Atlantic time zone (GMT -4).
The San Sebastián has a U5 Census Class Code which indicates populated place that is also a census designated place with the same name. It also has a Functional Status Code of "S" which identifies a statistical entity.