The name Bulahdelah ("Boolah Dillah", meaning the Great Rock), is the local Worimi Aboriginal people’s name for the mountain, on which the south-eastern sector of the township is built. The official name of the mountain is Bulahdelah Mountain, since 1818 when crown surveyor
John Oxley added the word Mountain, but it is commonly known as "the Alum Mountain".
Alunite was discovered on the mountain and mined from 1878 to 1927, managed by the Department of Mining from 1897. A refinery, "The Alum Works", was built to extract
alum from the alunite. The mine was operated again, from 1934 to 1952. Due to decreasing profitability, mining ceased by 1952 and, in 1979, NSW State Forests took over management of the mountain. Construction of the timber bridge across the
Myall River was completed in 1892 and the bridge was formally opened on 28 July 1892. A 2-lane
concrete bridge over the Myall River was completed in 1969. In 1970, the
Bulahdelah tornado swept through the nearby forests, just north of Bulahdelah in what was Australia's most destructive tornado on record. In July 2013 a new section of the
Pacific Highway bypassed Buladelah. ==Population==