| Kruostas | |
| Mouth Coordinates: | 55.3709°N 24.0077°W |
| Subdivision Type1: | Country |
| Subdivision Type2: | Region |
| Length: | 28.9km (18miles) |
| Discharge1 Avg: | 0.5 m³/s |
| Basin Size: | 99.7km2 |
| Tributaries Left: | Vinkšnupys, Žalčiupys, Suokupis, Alkas, Skaudinis, Latupys |
| Tributaries Right: | Konkulis, Vensutis |
The Kruostas is a river of Kėdainiai district municipality, Kaunas County, central Lithuania. It flows for and has a basin area of 99.7km2. It originates near Alksnėnai village and goes through agriculture fields passing the villages of Žilvičiai, Šlapaberžė, Beržai and Daškoniai. The lower course goes through a deep valley beside Vaidatoniai hillfort. This area is Kruostas botanic sanctuary. The river meets the Nevėžis from the right side near Urbeliai village. Vaidatoniai pond is on the Kruostas river.
The name Kruostas derives from Lithuanian word kruostas or skruostas ('cheek, eyelash, eyebrow'), further from skrosti, skersti ('to slice, to butcher').