San Isidro is a 6th class municipality in the province of Abra. Land Area is 35.9 Sq. Kms.

According to the 2000 census, it has a population of 4,293 people in 820 households.

San Isidro is politically subdivided into 9 barangays.

The place climate is characterized by 2 distinct seasons. The dry season, which occurs from November to April, is marked by daily blue skies and clear starry nights and the wet season for the rest of the year with high rainfall intensities accompanied by storms and typhoons.

Soil type is mostly Sandy Clay Loam