The rural municipality was (together with Idd) was merged with the city of Halden on 1 January 1967.
By a royal proclamation in 1769, Berg became the head of its own district with Rokke and Asak as annexes.
The name is identical with the word berg meaning 'rocky hill; mountain'.
The edifice is in Romanesque style and built of brick with natural stone in the corners.
The medieval era building has an oblong nave and a smaller square choir.