Abra de Ilog was formerly a small settlement founded by Spanish religious missionaries sometime in the early part of the 17th century. According to folk history, its former name was Abre de Ilog. The name was derived from the Spanish verb abrir (to open) and the Tagalog noun ilog (river). Later on, the name evolved into its present name: Abra de Ilog, a Chabacano-like terminology which can be loosely translated as bucana ng ilog, or "opening of the river." This can be attributed to the numerous rivers and creeks that traverses strategic areas of the municipality.
In 1902, during the American Occupation the town was officially organized. Abra de Ilog's first "municipal president" was Rosaleo Miciano. But with the passage of Republic Act No. 1280 (An Act Reducing the Fifteen (15) Municipalities of Occidental Mindoro into Eight (8) Municipalities) on January 4, 1905, Abra de Ilog was made a barrio of the Municipality of Mamburao.