The crest is flat and slightly hilly reaching an altitude of 300-450 m with rounded peaks, the highest being Gyurgenbair (555 m), situated in Bulgarian territory at 2 km to the south-west of the village of
Kraynovo. Dervent Heights are formed mainly by
limestone and
granite. There are small deposits of iron and copper ore. The climate is Mediterranean. Several rivers have their source in the heights, including
Popovska reka (72 km),
Arapliyska reka (42 km) and
Boyalashka reka (33 km) (belonging to the Tundzha basin in Bulgaria), and Tatardere, Havsadere and Chengerdere (tributaries of the
Ergene in Turkey). Large areas of the crest and the slopes are covered with deciduous forests and pastures. Dervent heights are included in the
European Union network of nature protection areas
Natura 2000. == Settlements ==