The B4635 follows the original route of the A41 through Tring. It was renumbered as part of the A4251 when the A41(M) Tring bypass opened, then downgraded to its present number when the A41 Berkhamstead bypass opened.
The road starts at a dumbbell GSJ on the A41 at the top of Tring Hill, where it also meets the B4009 to the southwest and B488 to the northeast. Our road heads vaguely eastwards past fields and a cemetery before becoming built-up. The original route of the road obviously continued across Tring Park but it was rerouted in the 18th century and so the B4635 bears left onto Western Road into the town centre.
After crossing a mini-roundabout we run onto the High Street, which is deliberately narrowed and traffic-calmed, yet remains the two-way B4635. This takes us to another mini-roundabout, where the B486 bears off left and we bear round to the right to reenter open country. There's a large wall on the right, at one time the boundary of Tring Park, although the wall has now been breached in a few places to provide access to newer housing and a Tesco. It's not long before another dumbbell GSJ is reached and the road ends as it returns to the A41; the A4251 continues ahead.