This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations .(March 2025)  | 
| Hertford Lock | |
|---|---|
|   The lock and lock-keeper's cottage  | |
    | |
| 51°48′14″N0°04′00″W / 51.803799°N 0.066739°W | |
| Waterway | River Lee Navigation | 
| County | Hertfordshire | 
| Maintained by | Canal & River Trust | 
| Operation | Manual | 
| Length | 85 feet (25.9 m) | 
| Width | 16 feet (4.9 m) | 
| Fall | 7 feet 11 inches (2.4 m) | 
| Distance to  Bow Creek  | 26.3 miles (42.3 km) | 
| Distance to  Hertford Castle Weir  | 0.8 miles (1.3 km) | 
Hertford Lock (No1) is a lock situated on the River Lea on the eastern side of Hartham Common, Hertford in the English county of Hertfordshire. It is owned and managed by Canal & River Trust and is the first lock of the River Lee Navigation.
 The lock is located on the River Lee Navigation towpath which forms part of the Lea Valley Walk