The Hase is a 169.7-kilometre (105.4 mi) long river of Lower Saxony, Germany.^[1] It is a right tributary of the Ems, but part of its flow goes to the Else, that is part of the Weser basin. Its source is in the Teutoburg Forest, south-east of Osnabrück, on the north slope of the 307-metre (1,007 ft) high Hankenüll hill.

After about 15 kilometres (9 mi), near Gesmold and about 6 kilometres (4 mi) west of Melle, the Hase encounters an anomaly of terrain and bifurcates such that each branch flows in a different drainage system:

• one third of its waters flow along the south side of the Wiehengebirge hills eastward from Gesmold into the Else, which begins there, and flows into the Werre at Kirchlengern (north of Herford). The Werre is a tributary of the Weser.
• two thirds of its waters (the Hase proper) flow northwest from Gesmold toward Osnabrück, past the towns listed below, and toward Meppen, where the Ems receives its flow.

• Melle
• Bissendorf
• Osnabrück
• Wallenhorst
• Bramsche - to the south of this city the Hase crosses the Mittelland Canal
• Rieste
• Alfhausen - here the Hase forms the Alfsee, an artificial lake acting as flood retention basin for the lower reaches
• Bersenbrück
• Badbergen
• Quakenbrück - in the southeast the Hase divides into two branches: the Big Hase (passing the town in the northeast) and the Little Hase (which itself is divided into several branches within the town, one of which leaves the town northwards to the Big Hase) (Binnendelta)
• Menslage - here the Hase is channeled into the Little Hase
• Löningen - here it flows into a somewhat northerly branch: the Big Hase
• Herzlake - here the two branches flow together again
• Haselünne
• Meppen

Currently one Run-of-the-river hydroelectricity is installed

• List of rivers of Lower Saxony