Omberg
Omberg is a forested mountain in western Östergötland County in Sweden. Administratively it is split between the municipalities of Ödeshög in the south and Vadstena in the north. It lies between Lake Vättern and Lake Tåkern. Alvastra Abbey lies at its foot.
Geologically Omberg is a horst, a fault-bounded and uplifted block of bedrock. The western cliff of Omberg has been indicated as an ättestupa in folk history.