| Mărcușa | |
| Name Other: | Cernat |
| Pushpin Map: | Romania |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Covasna County |
| Subdivision Type3: | Villages |
| Subdivision Name3: | Cernat, Mărcușa |
| Length: | 24km (15miles) |
| Mouth: | Râul Negru |
| Mouth Coordinates: | 45.8868°N 26.0776°W |
| Basin Size: | 89km2 |
The Mărcușa (also: Cernat) is a right tributary of the Râul Negru in Romania. It flows into the Râul Negru between the villages Mărcușa and Surcea.[1] Its length is 24km (15miles) and its basin size is 89km2.
The following rivers are tributaries to the river Mărcușa (from source to mouth):