| 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, Hertfordshire, England.
Directly behind the lock is Carthagena Weir, part of a fishery which also includes two lakes and a section of the Old River Lea. To the east of the lock is the Nazeing Mead complex of lakes which incorporates part of the River Lee Flood Relief Channel.
Vehicular access is via the B194 Nazeing New Road. Pedestrian and cycle access is via the towpath which forms part of the Lea Valley Walk.