San Isidro, officially the Municipality of San Isidro (Ilocano: Ili ti San Isidro; Tagalog: Bayan ng San Isidro), is a 5th class municipality in the province of Abra, Philippines. According to the 2015 census, it has a population of 4,574 people.
San Isidro is located at 17°28′N 120°36′E.
According to the Philippine Statistics Authority, the municipality has a land area of 48.07 square kilometres (18.56 sq mi) constituting 1.15% of the 4,165.25-square-kilometre- (1,608.21 sq mi) total area of Abra.
San Isidro is politically subdivided into 9 barangays.
In the 2015 census, San Isidro had a population of 4,574. The population density was 95 inhabitants per square kilometre (250/sq mi).