World War II: Filipino troops of the 15th, 66th and 121st Infantry Regiment, Philippine Commonwealth Army, USAFIP-NL liberate the captured in Ilocos Sur and start the Battle of Bessang Pass in Northern Luzon.
The Battle of Bessang Pass (Filipino: Labanan sa Pasong Bessang; Ilocano: Gubat ti Paso Bessang) was a major battle during the Philippines Campaign of World War II. It was fought from 9 January through 15 June 1945 in Cervantes, a municipality in the province of Ilocos Sur, located 382 kilometres (237 mi) north of Manila. The area serves as a gateway to the Cordillera mountains and the city of Baguio. Bessang Pass was a stronghold of the Japanese imperial forces under Gen. Tomoyuki Yamashita, known as the Tiger of Malaya and conqueror of Singapore. It was part of the triangular defense of General Yamashita in the north, namely the Balete Pass, Villaverde Trail and Bessang Pass, guarding the Ifugao-Benguet-Vizcaya borders. Its fall at the hands of the United States Army Forces in the Philippines - Northern Luzon (USAFIP-NL) on June 14, 1945 paved the way for the entrapment of Yamashitas forces in the Cordillera until the generals surrender in September 1945.
Ilocos Sur (Ilocano: Makin-abagatan nga Ilocos) is a province in the Philippines located in the Ilocos Region in Luzon. Its capital is the city of Vigan, located on the mouth of the Mestizo River. Ilocos Sur is bordered by Ilocos Norte and Abra to the north, Mountain Province to the east, La Union and Benguet to the south and the South China Sea to the west.
Ilocos Sur was founded by the Spanish conquistador, Juan de Salcedo in 1572. It was formed when the north (now Ilocos Norte) split from the south (Ilocos Sur). At that time it included parts of Abra and the upper half of present-day La Unión. The current boundary of the province was permanently defined through Act 2683, which was signed in March 1917.
The province is home to two UNESCO World Heritage Sites, namely, the Heritage City of Vigan and the Baroque Church of Santa Maria.