| River Sem | |
|---|---|
  Location of the mouth within Wiltshire | |
| Location | |
| Country | United Kingdom |
| Region | Wiltshire |
| Physical characteristics | |
| Source | |
| • location | East Knoyle, Wiltshire, England |
| • coordinates | 51°04′25″N 2°10′04″W / 51.0737°N 2.1678°W |
| Mouth | |
• location | Wardour, Wiltshire, England |
• coordinates | 51°02′45″N 2°06′37″W / 51.045790°N 2.110142°W |
• elevation | 98 m (322 ft) |
| Length | 7.03 km (4.37 mi) |
| Basin size | 25.6 km2 (9.9 sq mi) |
The River Sem is a natural waterway that flows through the ceremonial county of Wiltshire in England. It flows approximately 4+1⁄4 miles (7 km) from its source near East Knoyle to join the River Nadder near Wardour.[1]