Bauang is a first class urbanized municipality in the province of La Union, Philippines. According to the 2015 census, it has a population of 75,032 people. It is bordered by San Fernando City to the north, Caba to the south, Naguilian to the east, and the West Philippine Sea to the west. The MacArthur Highway runs through the town, which junctions with Naguilian Road, one of the mountain roads leading to Baguio City. ^ Census of Population. "Region I ".