IG3: 1.9 m clear of the highest tide in the London Bridge ledgers

The lowest postcode in IG3, IG3 9FP, stands 1.9 m above the highest tide in the London Bridge ledgers (5.41 m, 1 February 1953). The highest, IG3 8ZA, stands 20 m above it.
- Ground at eight in ten of its postcodes: between 9.3 m and 18 m, measured from Ordnance Datum; the middle one stands at 13 m.
- None lies in the Environment Agency's Flood Zone 3 from the sea.
- In Redbridge.