| Gadar River | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Iran |
| Subdivision Type2: | Province |
| Subdivision Name2: | West Azarbaijan province |
| Length: | 100km (100miles) |
| Discharge1 Avg: | 0.34m3/s |
| Mouth Location: | Lake Urmia, Iran |
| Basin Size: | 2000km2(approx.) |
The Gadar River rises in the Iranian Zagros Mountains close to where the borders of Iran, Turkey and Iraq meet. From its source, the river flows towards the southeast and then changes course due east through the Ushnu-Solduz valley. After leaving the valley, the river turns north and flows into the marshes bordering the endorheic saltwater Lake Urmia. The length of the river is approximately, its drainage basin is variously estimated as and and its discharge is per second. The Ushnu-Solduz valley has been occupied for many millennia, as testified by the excavations at sites like Hasanlu Tepe and Hajji Firuz Tepe.