The B321 is an approach road to Richmond Park in west London. The route was originally unclassified but appears to have gained its number by 1932.
It starts at a sharply angled junction on the A307 just to the south of Richmond Bridge. The road climbs away along the one-way Hill Rise. The first road on the right is the two-way Compass Hill, which leads back to the A307.
Still one-way, the B321 climbs Richmond Hill out of town. The houses on the right are soon replaced by the Terrace Gardens, which slope steeply downhill back to the A307. It's not long before we reach a T-junction. Left is the B322 and the B321 TOTSOs right and finally becomes two-way. The road continues to follow the Terrace Gardens to the far end, then passes the Richmond Hill Hotel on the left before ending at a mini-roundabout on the B353 by the Royal Star and Garter Home and a stone's throw from the Richmond Gate into Richmond Park.
