Standing 583 metres above sea level, the mount Kottmar is part of the Lusatian mountain region and belongs to the administrative district of Görlitz. Just like the nearby mountains Schlechteberg in Ebersbach and Löbauer Berg in Löbau, it is an extinct volcano of tertiary volcanism and consists of phonolite (clink-stone), which is a volcanic rock.
One of the three sources of the river Spree as well as the Cunnersdorfer Wasser spring is found at Kottmar mountain. Via the Spree, both flow into the North Sea. Another watercourse having its source at the foot of the Kottmar, the so-called Petersbach, flows - via the Lusatian Neiße and Oder rivers - into the Baltic Sea. Thus, Kottmar mountain is part of the Upper Lusatian watershed.
