Aarberg is a municipality in the Seeland administrative district in the canton of Bern in Switzerland.Aarberg lies 20 kilometers from Bern above the Aare River. With an area of 7.93 km2 (3.06 sq mi), Aarberg borders Bargen, Kappelen, Lyss, Radelfingen and Seedorf.Aarberg is not to be confused with Aarburg in Aargau or with Aarbergen in Germany.The city was once located on an island with the Aare River and Little Aare River (Kleine Aare) flowing around it.