Agoncillo is a 4th class municipality in the province of Batangas, Philippines. It is located 120 km south of Manila, a two hour drive via the scenic route of Tagaytay Ridge and R. Diokno Highway It is 32 km away from Batangas City, the provincial capital. Bounded in the east by approximately 10 km lakeshore of Taal Lake, in the south by the municipality of San Nicolas, separated by Pansipit River on the west by the municipality of Lemery and on the north by the municipality of Laurel. According to the 2000 census, it has a population of 26,584 people in 5,029 households.
The current set of local government officials were elected in 2007 and their term will expire in 2010. The municipal mayor is Glorioso R. Martinez. Mario M. Atienza is the vice mayor and presiding officer of the Sangguniang Bayan which is composed of May Lacap - Martinez, Michael John M. Humarang, Herman C. Brotonel, Leonarda A. Enriquez, Buenaventura V. Carolino, Maurice E. Punzalan, Mario P. Balba and Ador D. Alcantara.
The town of Agoncillo was originally a part of Lemery. In 1945, an executive committee was formed by the first appointed Mayor Jacinto Mendoza Sr. to prepare a resolution, requesting the Secretary of the Interior, Malacanang, through the provincial board to detach and separate 11 barrios and be created a municipality.
Finally, on April 17, 1949, Executive Order No. 212 was issued by President Elpidio Quirino, lifting the suspension and thereby, authorizing the immediate organization of the Municipality under the name of Agoncillo, in honor of Don Felipe Agoncillo, a native of Taal and one of the first Filipino representatives to the Spanish Cortez.