The Semnones were a Germanic people, and more specifically a Suebi people, who lived near the Elbe river in the 1st and 2nd centuries AD, during the time of the Roman empire.
The 2nd century geographer Claudius Ptolemy places the Semnones between the Elbe and "Suebos" river. Modern scholars believe that the Suebos was the Oder. However, archaeological evidence suggests they stretched as far as the Spree and Havel rivers in the east, and not quite as far as the Oder. To their north was another part of the Havel, and to the south the Fläming Heath. In present day terms they were therefore in the area between the modern cities of Magdeburg and Berlin.