The Hamme is a 48 km long river in Germany, Lower Saxony, north-east of Bremen. Its source is north of Osterholz-Scharmbeck. It flows through the moors north-east of Bremen called Teufelsmoor (German for dead moor), and meets the river Wümme in Ritterhude. From this junction, the river is called Lesum. The Lesum flows into the river Weser in Bremen-Vegesack.
On the river Hamme there are many water-sport clubs, for example the Wassersportclub Hamme e.V. (watersports-club Hamme), the Ruder-Verein Osterholz-Scharmbeck von 1901 e.V. (Rowing Club Osterholz-Scharmbeck since 1901) and the Segel Club Hamme e.V. (Sailing Club Hamme).