|Location Map ( geo)|
|Distance:||1.8 miles (2.9 km)|
The C21 starts on the A2 on Corporation Street, Rochester, as Northgate. After passing the Corn Exchange and Registry Office, the road crosses the old, cobbled, Rochester High Street. The C21, now Boley Hill, avoids the historic Northgate, emerges outside of Rochester Cathedral. The cobbled C21 then follows the moat of Rochester Castle. The road continues south, passing King's School and other numerous historic properties, while also being very narrow in places. Soon, the road widens and becomes St Margaret's Street before passing Fort Clarence and becoming the Borstal Road. The road becomes busier once C370 Priestfields joins from the east, and the road continues to be lined with terraces. Shortly after, the C21 becomes Wouldham Road, before passing under the M2. From here, the road is surrounded by countryside, and it is not clear if the designation of C21 ends here, or continues to the authority boundary.
Tour de France
The entire length of the C21 was used as part of Stage 1 of the 2007 Tour de France .