National Cycle Route 21

National Cycle Route 21 (or NCR 21) is part of the United Kingdom's National Cycle Network. It runs from Greenwich in South-East London south to Crawley, then east to Groombridge and south to Eastbourne, with a short final loop northwards again to its end at Pevensey.

The route is approximately 150 km (93 miles) long. Several sections are not suitable for road bikes.

Links to:

• National Cycle Route 4 at Greenwich which is the route's start.
• National Cycle Route 1 at Greenwich is a few hundred metres from the route's start.
• National Cycle Route 2 at Polegate and at Pevensey at the route's finish.
• National Cycle Route 20 at Redhill and at Crawley.

The route forms much of the English section of the Avenue Verte, a planned long-distance cycle route linking London and Paris.