The origins of the Great East Road are not explained in any detail, but the fact that it ran from Lindon toward Rivendell implies that it was created, or at least adopted, by the Elves who dwelt in those two locations. Rivendell was founded in II 1697, so the road probably appeared after that time. To complicate matters, however, Rivendell stood near one of the few passes over the Misty Mountains, and conceivably the Great East Road (or an earlier version of the same route) might have been made to carry traffic over the High Pass before Rivendell existed. If there were such an earlier incarnation of the Great East Road, it was likely the work of the Dwarves, who made many of the earlier roads in Middle-earth.

During the Third Age, the Great East Road ran for much of its length through the lands of Arnor. The Dúnedain were great builders, and we have accounts of them strengthening the bridges on the road for the passage of their armies during the War of the Last Alliance, as well as working to maintain the roads that ran through their realms. The last kingdom of the Northern Dúnedain fell long before the end of the Third Age, and after that time the more remote parts of the Great East Road would have fallen into disuse and disrepair.

Canonical maps showing this road mark its western end at Michel Delving in the Shire. We know from textual references that it - or perhaps an extension of it - could be followed as far westward as the Grey Havens, and this conjectured westward section is shown with a dashed line here. We also know that it was frequented by Dwarves out the Blue Mountains, so further connecting roads likely existed at its western end, running up into the mountains to the mines of the Dwarves.