Bacnotan, officially the Municipality of Bacnotan (; ), is a municipality in the province of La Union, Philippines. According to the , it has a population of people.
The name Bacnotan may come from the word "bakunuttan", which means "to flog".
Around 1571, the Spaniards occupied Ilokos Province. In February 2, 1818, the Real Cedula separated the region into two parts: Ilocos Norte and Ilocos Sur. Bacnotan is part of the Ilocos Sur around the time. Around 1846 to 1849, La Union was established, and that province included Bacnotan.
The Municipality of Bacnotan is surrounded by Balaoan from the North, San Gabriel from the east, and San Juan from the south, and South China Sea from the west.
As of 2020, Bacnotan is politically subdivided into 47 barangays. Each barangay consists of puroks and some have sitios.
The climate in Bacnotan is dry from November to May and wet from mid-May to October. The south-west monsoon brings an abundant rainfall experienced during the wet season. The relatively dry season is caused by the north-east monsoon passing over the Cordillera Mountain Range. Average temperature is .
The household population of Bacnotan as of the 2024 Census of Population and Housing, was recorded at 45,203 people.
As of 2020-2021, in the public sector, there are 16 elementary schools, 1 public secondary school, and 1 public integrated school that offers K to 12 education. In the private sector, there are 2 private elementary schools and 1 private secondary school. There is 1 state university for higher education.
Bacnotan, belonging to the first congressional district of the province of La Union, 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.
Bacnotan has produced notable personalities in various endeavors. Some of them are as follows: