EN3: 7.7 m clear of the highest tide in the London Bridge ledgers

The lowest postcode in EN3, EN3 4GH, stands 7.7 m above the highest tide in the London Bridge ledgers (5.41 m, 1 February 1953). The highest, EN3 4NN, stands 27 m above it.
- Ground at eight in ten of its postcodes: between 15 m and 21 m, measured from Ordnance Datum; the middle one stands at 17 m.
- None lies in the Environment Agency's Flood Zone 3 from the sea.
- In Enfield.