The river Kruoja flows in Radviliskis, Siauliai and Pakruojis districts, the river Musa right tributary. Length of the river 60 km, the basin area 355 km ². The source in small lake at Kirbaiciai village, 5 km northwest from Radviliskis town. Flows to the northeast. Flows into the river Musa 94 km from its confluence with the river Nemunelis at Petrasiunai village. The riverbed width 5-7 m, depth 0.4-0.7 m. Average gradient 108 cm / km. The river valley width 300-400 m, floodplain width 150-200 m. Speed of current 0.01-0.1 m/s, at sprig flood up to 1 m/s. Average rated discharge upstream the brook Skalvis 0.22 m³/s, at the mouth 1.74 m³/s. In cold winters the river freezes to the bottom.

At higher water level. Spring, autumn or in summer after heavy rains.
Shalows, dam, a few strainers, water plants.
WW 0 (1-).

10.0 Bridge. Pakruojis. Current calm.
9.8 Bridge. Pakruojis.
9.6 Pedestrian bridge. Pakruojis.
8.6 Bridge. right Pakruojis.
8.4 right Sile. right Pakruojis manor. The river is dammed, a few small islands.
7.7 Pakruojis manor water mill dam. Old arched bridge. The river flows through an artificial watercourse.
7.1 The river flows in natural riverbed through meadows. Width 4-10 m. The banks low, bare, in some places a few trees.
6.2 Small bridge. left Nereikoniai.
5.8 Pedestrian bridge. left Nereikoniai.
4.7 Hanging pedestrian bridge. right Akmeneliai.
4.4 left Kvedarai. right Akmeneliai.
3.1 left the brook K-1. right Akmeneliai.
0.8 right Petrasiunai.
0.0 The Kruoja flows into the river Musa.