Gregorio del Pilar, officially the Municipality of Gregorio del Pilar (; ) is a municipality in the province of Ilocos Sur, Philippines. According to the , it has a population of people.
In the past, the name of the town used to be 'Ananaaw' before it was changed into Concepcion (in honor of its patron saint, Nuestra Senora de Concepcion). It was eventually renamed in memory of General Gregorio del Pilar on June 10, 1955 by virtue of Republic Act No. 1246, which was sponsored by Congressman Ricardo Gacula. The municipality is the site of the Battle of Tirad Pass, where General del Pilar and his men fought a last stand against the Americans.
On December 2, 1899, the United States 33rd Volunteer Infantry Regiment under Major Peyton C. March, prepared for an assault of the Filipino forces fortification under the command of General Gregorio del Pilar. On the narrow trail of Tirad Pass, the Filipino soldiers watched as the enemy began to move up the trail. On around a few hundreds yards above the pass, General Gregorio del Pilar, with his staff and accompanied by two civilians from Sitio Mabatano, spotted the American forces through his spy glass as they were starting to move. But as he watched, he noticed that the American forces broke formation and instead sent a messenger on horse back with a white banner. As the messenger was coming near the fortification of Filipino forces, the sound of a gun was heard and the messenger fell. The American forces divided into three separate groups. One group followed the trail towards the pass.
Another group ascended the hill facing the Filipino soldiers stationed in the pass. The third group, led by a Filipino from the lowlands named Januario Galut, made their way up unnoticed through the old trail which was hastily barricaded by felled trees a few days before the Americans arrived. This old path led to the place where General del Pilar stood watching. As the American forces dispersed, the general ordered the two civilians, Tucdaden and Abeng to proceed to the trenches and deliver the breakfast of the Filipino soldiers. All of a sudden, continuous gunshots were heard continuously and went unabated for several hours. General del Pilar was shot and killed.
The town lies among the western hills of the Cordilleras in the interior eastern portion of the province of Ilocos Sur. It is bounded to the north by the town of San Emilio, Quirino to the east, Sigay to the south, and Salcedo to the west. Its 7 barangays and sitios are connected by winding foot trails and seasonal rugged roads. The town is likewise endowed with natural scenery and wonders such as the payoh or rice terraces, pristine waterfalls, and the distinctive peak of Mount Tirad. There are also trails crisscrossing Tirad Pass, which were built through polo y servicio (forced labor) during the Spanish Period.
Gregorio del Pilar is situated from the provincial capital Vigan, and from the country's capital city of Manila.
Gregorio del Pilar is politically subdivided into 7 barangays. Each barangay consists of puroks and some have sitios.
Gregorio del Pilar is politically subdivided into 5 sitios.
In the 2024 census, Gregorio del Pilar had a population of 4,385 people. The population density was .
The inhabitants are Igorots, but belong to the Bag-o ethno-linguistic group. This mixture of Ilocano and Igorot intermarriages speak the Kankanaey language but can speak and understand the dialects of their neighboring towns. Many have already acquired college education and some serve the government and private institutions.
Gregorio del Pilar, belonging to the second congressional district of the province of Ilocos Sur, is governed by a mayor designated as its local chief executive and by a municipal council as its legislative body in accordance with the Local Government Code. The mayor, vice mayor, and the councilors are elected directly by the people through an election which is being held every three years.
The Salcedo-Galimuyod-Sigay-Del Pilar Schools District Office governs all private and public schools within the municipality of Gregorio del Pilar. The Schools District Office (SDO) also oversees the operations of all schools situated in Salcedo, Galimuyod, and Sigay.