| Carthagena Lock | |
|---|---|
 Below the lock | |
 | |
| 51°44′37″N 0°00′08″W / 51.743566°N 0.002108°W | |
| Waterway | River Lee Navigation |
| County | Hertfordshire Essex |
| Maintained by | Canal & River Trust |
| Operation | Manual |
| Length | 85 feet (25.9 m) |
| Width | 16 feet (4.9 m) |
| Fall | 5 feet (1.5 m) |
| Distance to Bow Creek | 17.5 miles (28.2 km) |
| Distance to Hertford Castle Weir | 8.8 miles (14.2 km) |
Carthagena Lock (No7) is a lock on the River Lee Navigation at Broxbourne