San Ildefonso, like many other places in the provinces at the beginning of the Spanish Regime, did not have a name. Stories have it that sometime in 1625, the town's inhabitants decided to give it a name, but nothing came out after more than five hours of discussions. So while thinking of a name, they decided to go fishing for a week. And while preparing to go fishing, they saw a box floating not far from shore. Wading to reach the box and carrying it ashore, they opened the box to find a statue of
Saint Ildephonsus. The young women of the place carried the statue to the center of the village, where it was enshrined in a small hut for many years. He became the patron saint of the municipality, and his name was decided to become the name of the fledgling municipality. San Ildefonso was a former
rancheria of Bantay before it became a municipality, but because of its size it was annexed to Santo Domingo as a barrio. In 1921, Assemblyman (and future Philippine president)
Elpidio Quirino worked to convert San Ildefonso into a municipality again.
200th Anniversary of Basi Revolt On September 28, 2007, San Ildefonso officials (Governor
Deogracias Victor Savellano and Rep.
Ronald Singson) commemorated the
Basi Revolt. Recently, the
Sangguniang Bayan of San Ildefonso approved a
resolution declaring September 16 as a non-working
holiday and named the old road in Barangay Gongogong as Ambaristo street in honor of
Pedro Ambaristo, leader of the
Basi Revolt. Mayor Christian Purisima enrolled
basi as their entry into the “
One Town; One Product” (OTOP) program of Governor Savellano. ==Geography==