The river Apse flowing Skuodas district, the river Bartuva right tributary. Length 40 km, the catchment area 357 km ². Source at Margininkai village, 4 km to the northeast from Ylakiai town. Flowing to the west. In upper reaches called the Vereta. On lower part of the river Lithuanian - Latvian border. Flows into the river Bartuva 47 km from its mouth, 4 km downstream from Skuodas.  Average gradient 246 cm / km. Valley is a narrow, dry, 20-30 m deep. Average discharge at the mouth 4 m³ / s.

All year. Recommended at higher water level.
Shallows, rapids, strainers.
WW 1- (1+).

31.7  Aleksandrija - Virsilai road bridge. left Kivyliai. On the river banks woods. In the river strainers. Stream calm.
31.3 left hillfort Kivyliai.
30.8 right A-2. The river divided to channels, many strainers.
30.1 right Sartis. right Zvaguli. The river is meandering on the Lithuanian-Latvian border. Many strainers. The river width 5-8 m. Marshy banks.
25.4 right Svirksty. Average gradient to  Gruntes village 126 cm / km.
24.7 left Klaisiai.
23.1 right tributary.
21.5 right Kadegi.
20.6 left Trubakiai.
18.3 right Gruntes. Average gradient to Poli village 34 cm / km. Current calm. Strainers reduced.
15.8 right Rune. The largest tributary of the Apse. Water in the river has increased significantly.  Current is slow.
15.4 left Dabrupis.
12.1 left Lendimas.
8.7 right tributary. right Sausi. The current speed is accelerated.
8.0 right Poli. Average gradient to Kanizeri village 83 cm / km. To the mouth strainers, several rapids. The river width  about 10 m. The banks are steep.
6.7 left Narvydziai.
5.8 Skuodas - Priekule road bridge. right Vaigori.
5.2 Railway bridge.
2.7  left Kanizeri. Average gradient to the mouth 89 cm / km.
0.0 The Apse flows into the river Bartuva.