With the creation of the Austrian municipalities ("Ortsgemeinden") in 1850, the three municipalities Luggau, Sankt Lorenzen, and Liesing were constituted. The cadastral communities ("Katastralgemeinden") Kornach and Strajach merged with the municipality of Mauthen, but in 1182 obtained independent status as the municipality of Unterlesach. Ten years later the two localities Birnbaum and Sankt Jakob became independent municipalities as well. Through Carinthian local government reform in 1973, the eastern Lesach municipality of Sankt Jakob merged with Kötschach-Mauthen, while the four western municipalities were merged into the present municipality of Lesachtal.