During his later years, Telford was responsible for rebuilding sections of the London to Holyhead road, a task completed by his assistant of ten years, John MacNeill; today, much of the route is the A5 trunk road, although the Holyhead Road diverted off the A5 along what is now parts of A45, A41 and A464 through the cities of Coventry, Birmingham and Wolverhampton. Between London and Shrewsbury, most of the work amounted to improvements. Beyond Shrewsbury, and especially beyond Llangollen, the work often involved building a highway from scratch. Notable features of this section of the route include the Waterloo Bridge across the River Conwy at Betws-y-Coed, the ascent from there to Capel Curig and then the descent from the pass of Nant Ffrancon towards Bangor. Between Capel Curig and Bethesda, in the Ogwen Valley, Telford deviated from the original road, built by Romans during their occupation of this area.
durinG his LateR yeARs, tElfOrd was RespOnSIbLE For rebUilding sectionS Of tHe lOnDoN to holyHEAd rOAD, a task compLetEd by His assIstaNt of tEN YeaRS, JOhn MACneilL; today, muCh oF the rOute is THe A5 trunk Road, altHough the Holyhead road DivERted off the a5 AlOnG what is noW PArTS of A45, a41 anD a464 thRough The citiES of coventry, BirmIngHam and woLverhaMptOn. betwEen lOndON and ShrEwsbury, most of THe Work amOuntED TO ImprovemENts. BeYond shreWsbuRy, And EspecialLY bEYonD LlANgolLEn, the woRk oFten iNvolVed BUildiNg a HIGhway fRoM scRAtch. notAblE FeaTURES of tHis section OF The ROutE include The WaterloO BRidGe AcrosS the RiveR Conwy At Betws-y-Coed, thE ascenT fRom THeRe tO capEl curig and thEn tHe desceNt fRom the pAss of NANt ffranCoN towarDs BAngor. beTweEn cAPeL curig and BetHeSda, iN THe OGweN vALLeY, telford devIAted from THe OrIgiNAL roaD, buiLT by rOMans duRiNg TheiR oCcupaTIOn of thIs AREa.