Isenberg
Isenberg was a County of medieval Germany. It was a partition of the county of Altena and was annexed to Limburg (Lenne) in 1242.
Counts of Isenberg (1191–1242)
- Eberhard I, Count of Berg-Altena count of Altena of the burg Altena on the river Lenne.
- Arnold of Altena count of Altena-Isenberg of the burg Isenberg on the river Lenne.
- Frederick of Isenberg count of Altena-Isenberg of the burg Isenberg on the river Ruhr.
- Dietrich I of Isenberg count of Limburg of the Hohenlimburg on the river Lenne.