The river Alantas flowing in Plunge and Kretinga districts, the river Minija left tributary. Length  39 km, the catchment area 139 km ². Source in swamps near Mižuikiai village, Flowing to northwest, empties into the river Minija 91 km from the mouth near Kartena town. Tributaries: Geldupis, Zvalginis, Karkluoje (all right). Riverbed is very windy. Average  gradient 227 cm / km. Valley deep (40 m). Rated discharge at at the mouth: maximum 30 m³ / s average 1.81 m³ / s, minimum 0.1 m³ / s. Runoff module is very high - 13 l / s of km ².

At higher water level. Spring, or after heavy rains.
Shallows, rapids, boulders, strainers.
WW 1+ (2).

7.4 right Karkluoje.
7.1  Velaiciai - Gaudutis road bridge. The gradient to the mouth 379 cm / km. River bed width 6-11m. The river runs through the forest. Rapids, small rapids, strainers, stones in the riverbed. The bridge can be reached from Klaipeda - Siauliai highway, at Dauginciai turn to south, to Gaudutis, Velaiciai direction. From the turning to the bridge 2 km.
6.1 right Rupsupis. right Gauduciai.
5.0 right hillfort Gauduciai.
4.0 left Tyrupalis. left Velaiciai. left hillfort Velaiciai.
3.2 right A-2. right close to the river  Klaipeda - Siauliai highway.
1.8 On old water mill dam site rapid.
1.7 left Duobupis. Bridge.
1.2 left A-1. right  Gintarai.
0.3  Kartena - Gargzdai road bridge.
0.2 Bridge.
0.0 The Alantas flows into the river Minija. Kartena town.