The Lee Navigation runs from the tidal river Thames at Limehouse Basin to a terminus at Hertford, and is 27.8 miles (44.5 km) long with 18 locks. The Stort Navigation joins the Lee near Hoddesdon and runs to a terminus at Bishops Stortford. The Stort Navigation is 13.8 miles (22.0 km) long and has 15 locks.
Bow Creek (the original tidal outlet of the Lee) joins the Navigation at Three Mills and joins the tidal Thames at Barking Road Bridge, after 1.3 miles (2.0 km) and Bow Locks.
There is also a network of Bow Back Rivers, restored as part of the 2012 Olympics site, which connect to the Navigation above Three Mills. With the reopening of Carpenter's Road Lock in 2017 the waterways are now navigable and passage can be booked through Canal & River Trust.
The maximum size of boat that can navigate the Lee & Stort Navigations is:
length (River Lee): 85' 4" (26.0 metres) - Old Ford Lock
length (River Stort): 89' 9" (27.4 metres) - Brick Lock
beam (River Lee): 16' 1" (4.9 metres) - Hardmead Lock
beam (River Stort): 13' 4" (4.1 metres) - Brick Lock
headroom (River Lee): 7' 8" (2.33 metres) - Kings Weir Bridge
headroom (River Stort): 6'10" - Keck's Bridge
draught (River Lee): 5' 11" (1.8 metres) - cill of Hardmead Lock
draught (River Stort): 4' 1" (1.24 metres)
A Sanitary Station key is required to operate locks 19 (Old Ford) to 12 (Rammey Marsh) on the River Lee, and locks 10 (Burnt Mill) and 6 (Sheering Mill) on the River Stort.
A booking with Canal & River Trust (7 days notice) is required to go through Carpenters Road, City Mill or Three Mills Lock.