Bornheim is a town in the Rhein-Sieg district, in North Rhine-Westphalia, Germany. It is situated on the West bank of the Rhine, approx. 10 km north-west of Bonn, 20 km south of Cologne.
The town borders on Bonn to the south, the towns of Alfter and Swisttal to the southwest, the town of Weilerswist to the west, the towns of Brühl and Wesseling to the north, as well as the Rhine-bordering town of Niederkassel in the east.
Bornheim is divided up into 14 districts: Bornheim, Brenig, Dersdorf, Hemmerich, Hersel, Kardorf, Merten, Rösberg, Roisdorf, Sechtem, Uedorf, Walberberg, Waldorf and Widdig.