[3] It was established as the municipality of Oteiza on June 16, 1962 by virtue of Republic Act No.

3489, from the municipality of Marihatag;[5] it acquired its current name on June 17, 1967 by virtue of Republic Act No.

[6] The town is famous for the Britania Group of Islands (or simply Britania Islets), a group of 24 islands with white sandbar beaches scattered across waters of the Lianga Bay, overlooking the Philippine Sea.

San Agustin is politically subdivided into 13 barangays.

Poverty incidence of San Agustin Source: Philippine Statistics Authority[11][12][13][14][15][16][17][18]