| Kalnik | |
| Source1 Location: | Mikrene Heights |
| Source1 Coordinates: | 42.9919°N 24.5775°W |
| Mouth Location: | Vit |
| Mouth Coordinates: | 43.0636°N 24.2575°W |
| Progression: | Vit→ Danube→ Black Sea |
| Subdivision Type1: | Country |
| Subdivision Name1: | Bulgaria |
| Length: | 41km (25miles) |
| Source1 Elevation: | 667m (2,188feet) |
| Mouth Elevation: | 250m (820feet) |
| Basin Size: | 263km2 |
The Kalnik (bg|Калник) is a 41 km-long river in northern Bulgaria, a right tributary of the river Vit, itself a right tributary of the Danube.
The Kalnik takes its source from the Tolev Spring at an altitude of 677 m, on the southern foothills of the Mikrene Heights of the fore-Balkan, some 1.5 km north of the village of Borima. Throughout its whole course the river flows westwards with a slight deviation to the north in a wide valley between the Mikrene Heights to the north and the Vasilyovska Mountain to the south. It flows into the Vit at an altitude of 250 m at the Boaza locality, south village of Peshterna.
Its drainage basin covers a territory of 263 km2 or 8.2% of the Vit's total.
The Kalnik has rain, snow and karst spring feed with high water in April–June and low water in July–October. The average annual discharge is 0.96 m3/s.
The river flows entirely in Lovech Province. There are three villages along its course: Staro Selo in Troyan Municipality, Vasilkova Mahala in Slavshtitsa, Ugarchin Municipality and Balgarski Izvor in Teteven Municipality. Its waters are utilized for irrigation. The Sopot Reservoir with a volume of 61.8 million m3 is located in its upper course.
There are two roads of the national network though the Kalnik valley, a 12.3 km stretch of the first class I-4 road Yablanitsa–Veliko Tarnovo–Varna between Boaza and the village of Sopot, Lovech Province, and a 16 km section of the third class III-402 road Sopot–Troyan between Sopot and Staro Selo.[1]