Dating the East-West Road is difficult, and indeed it may very well be the case that different parts of the road were laid at different times. The fact that it ran from the Elf-havens of Lindon towards Rivendell implies that the basic route was in place after Rivendell's founding in II 1697. It may have been even older than this (the eastern end might in principle have led to the High Pass over the Misty Mountains, rather than directly to Rivendell). Whatever the origins of individual parts of the East-West Road, the route itself would have been in place for thousands of years at the end of the Third Age (thus certainly earning its occasional alternative name of the 'Old Road').

While it's established that the East-West Road ran as far westwards as the Grey Havens on the Gulf of Lune, we do not have details of its route after it left the Westfarthing of the Shire. The conjectural route shown by a dashed line includes a speculative detour to the Tower Hills, a place of importance to both the Elves of Lindon and the Dúnedain of Arnor.