Barrancabermeja is a city in Colombia, located on the shore of the Magdalena River, in the western part of the department of Santander. It is home to the largest oil refinery in the country and is the capital of the Province of Mares. Barrancabermeja is known as the Oil Capital of Colombia. It is located 114 km west of Bucaramanga, on the banks of the Magdalena River in the Middle Magdalena region, which is the largest municipality and second in the entire department.