Altenberg (German: [ˈaltn̩bɛʁk] ) is an Ortsteil (area) in the municipality of Odenthal in the Rheinisch-Bergischer Kreis of the State of North Rhine-Westphalia, Germany, and was formerly the seat of the Counts of Berg. Over the course of time, they created around their Residence a small dominion, which later came to be called the Bergisches Land.