..the land was almost flat, and the waters became sluggish, tending to spread into fenland. Above Tharbad the river forked, with both branches having converged from out of a network of swamps, pools and eyots, where the only inhabitants were hosts of swans, and many other waterbirds.
In the early Second Age, this huge fenland north-east of Tharbad, which the elves named 'Nîn-in-Eilph', the 'Swanfleet', entered the southern part of the Ñoldorin realm Eregion, and Tharbad is first mentioned in the sixth century of that Age;
Such early river voyages were made by "hardy explorers" of Númenor, in "ships of smaller draught" (UT), but such journeys up the Gwathló increased rapidly after the Númenóreans constructed a small harbour at the river's estuary to exploit the local timber: 'Vinyalondë', 'the New Haven'.
By S.A. 1695, the Númenóreans were devastating the forests below Tharbad, and had been obliged to build forts both at the Haven and along the river, to protect their ship-building yards and "great wood-stores"(UT) from the local population, who were understandably hostile:
..the Númenóreans treated them as enemies, and became ruthless in their fellings, giving no thought to husbandry or replanting. 
Despite overrunning all of Eriador in the war which began in that year, Sauron's armies had eventually been forced back to the fortified River Gwathló, where they were held. Beforehand, Sauron:
"..had not enough force to spare for any assault upon the forts.."(UT), but late in the war he was reported to have
..summoned more forces, which were approaching from the south-east, and were indeed in Enedwaith at the Crossing of Tharbad, which was only lightly held.
Whether Tharbad's defences - which presumably consisted of the most northerly of the Gwathló's river forts - were overcome is uncertain, but Tharbad did become the site of The Battle of the Gwathló, where after having his army caught in the rear by Ciryatur, who had hurried up the Gwathló from Lond Daer, "Sauron was routed utterly.." (UT).
Tharbad is not mentioned in surviving records for more than 1500 years after the war: the whole region was largely ignored by the elves and the Númenóreans following the destruction of Eregion and the forests "and the continued hostility of the surviving natives."
In the early days of the kingdoms the most expeditious route from one to the other (except for great armaments) was found to be by sea to the ancient port at the head of the estuary of the Gwathlo and so to the river-port of Tharbad, and thence by the road.
A need had arisen "..to undertake the great works of drainage and dyke-building that (would make) a great port on the site where Tharbad stood.." (UT).
The ford was deepened to receive sea-going vessels, and the massive fenlands above it were extensively drained, until a much smaller Swanfleet was all that remained. Tharbad's new river-port was spanned by a bridge, the immense labour of which "was shared by the North and South Kingdoms", and included "a fortified town and haven about the great bridge over the Greyflood.." 
These fortifications around the town were "raised there on great earthworks on both sides of the river.." (UT), and 'The Great South Road', which was built at the same time to connect the two nations, passed across the bridge via "long causeways that carried the road to it on either side across the fens.." (UT).
Some things did not change, however : Tharbad was the only settlement of Númenóreans in Enedwaith, because the area beyond the fortified town "was of little concern to them, except for the patrolling and upkeep of the Great Royal Road" (UT). To this end, "A considerable garrison of soldiers, mariners and engineers [were] kept there until the seventeenth century of the Third Age.." (UT).
From about T.A. 1150, it is recorded that a tribe of hobbits migrated to the fens above Tharbad, and spread onto the land along the Causeway south-east of the town over several centuries, but they left around T.A 1630;
..because the land and clime of Eriador, especially in the east, worsened and became unfriendly.
Their departure and the deterioration in the weather occurred around the time of the Great Plague of S.A. 1636, which almost completely depopulated Cardolan, one of Arnor's 'successor states' with whom Gondor shared Tharbad. Cardolan's few surviving Dúnedain - including those in Tharbad - fled west to Arthedain. Gondor too was devastated, and in the years following the Plague, traffic along the road through Tharbad would have declined considerably, as "many parts of Eriador (had become) desolate." (LR): little wonder that "from then onwards, the region fell quickly into decay.." (UT).
Survivors of the Plague did remain in Tharbad, and the Great (now Old) South Road continued to be an important trade route for another 350 years until the fall of Arthedain in T.A 1974, and the end of the 'days of the Kings' in Gondor 74 years later. From T.A. 2050, the nearby native Dunlendings, as well as the people left in Tharbad no doubt;
..ceased in fact to be subjects of Gondor; the Royal Road was unkempt in Enedwaith, and the Bridge of Tharbad became ruinous, and was replaced only by a dangerous ford.
Tharbad was still inhabited for another 862 years, despite the absence of any sort of central government, presumably by a people akin to the Bree-men and Dunlendings. During this period, the decrepit remains of the Great South Road above Tharbad became known as 'The Greenway', even after Tharbad itself was finally "ruined and deserted"(LR) in T.A. 2912, when great floods devastated Enedwaith following the Fell Winter.
By the time of The War of the Ring a century later;
When Boromir made his great journey from Gondor to Rivendell - the courage and hardihood required is not fully recognized in the narrative - the North-South Road no longer existed except for the crumbling remains of the causeways, by which a hazardous approach to Tharbad might be achieved, only to find runs on dwindling mounds, and a dangerous ford formed by the ruins of the bridge, impassable if the river had not there been slow and shallow - but wide.
In the early Fourth Age, the "ruined town" (LR) was probably rebuilt and resettled at last, both by the Rohirrim - who colonized Enedwaith and "multiplied exceedingly" (LR) - and the Reunited Kingdom, which began to repopulate Eriador.
Sindarin for 'The Crossing Place'
Tharbad was possibly inspired by the Hall Green village in Warwickshire, England.
- "...Hall Green village was only a little distance away [from Sarehole] down a lane and across a ford."
- ― J.R.R. Tolkien: A Biography
- ↑ 1.0 1.1 1.2 1.3 1.4 J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, The History of Galadriel and Celeborn
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, Aldarion and Erendis
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Peoples of Middle-earth
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Peoples of Middle-earth, Of Dwarves and Men
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix A
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, The Battles of the Fords of Isen