Barangay San Isidro was formerly called "Gaboc". GABOC is blessed with fertile valleys and plains, the farmers used to experience excess of farm products which spoils or become "gaboc". The community residents used to have more than enough food for their daily consumption. Thus the old name of the locality as "gaboc" or spoils. As farmers, the community residents have chosen St. Isidore Labradore, the patron saint of the National Rural Life Conference, to be also their patron saint. St. Isidore or Isidro, was born in Madrid, Spain, who spent his life as a humble farm worker.

Barangay Captain Anacleto A. Sandulan with his Barangay Council passed a resolution changing the name of Gaboc to San Isidro, which was approved by a majority of its constituents in a plebiscite. It was indorsed to the Sangguniang Panlungsod, and was approved on April 1969.

San Isidro is divided into seven districts. In has an area of 429.42 hectares. It has a population of 4,173approximately where voting population is 1, 821 as of 2007. It has one elementary school and one newly established high school. It has 3 Day Care Centers. It has a wide multi-purpose pavement where the barangay hall is located. It has one primary health center and has one Roman Catholic church where in the people are mostly Roman Catholics. About 60% of the residents are gainfully employed in government & private offices & establishments, while 25% rely on farming or agriculture and 15%are jack of all trades.