Tharbad

[The Mouth of Sauron]

I remember reading somewhere that Gondor retained some kind of presence at Tharbad until the year 2912 of the Third Age. With Gondor's bounds diminished by then and Arnor ancient history, why would Gondor have maintained a garrison at Tharbad until 2912?

[Morthoron]

Originally Posted by The Mouth of Sauron

I remember reading somewhere that Gondor retained some kind of presence at Tharbad until the year 2912 of the Third Age. With Gondor's bounds diminished by then and Arnor ancient history, why would Gondor have maintained a garrison at Tharbad until 2912?

There is no indication the Gondorions had a garrison in Tharbad as late as 2912, Third Age. After the Great Plague of 1636, the population was radically reduced, and it seems likely that by the time of the ending of the reign of the last Gondorion king in 2050, only the ancestors of the Dunlendings and Bree-men lived there, no longer subject to Gondor. The Royal Road was no longer kept, and eventually became known as the Greenway, due to it resembling the rutted remnants of old Roman roads that were still accessible centuries after the collapse of Rome in France and England.

A note attached to the essay on "The Muster of Rohan" (in Unfinished Tales) states the following:

When the days of the Kings ended (1975-2050) and the waning of Gondor began, they ceased in fact to be subjects of Gondor; the Royal Road was unkept in Enedwaith, and the Bridge of Tharbad becoming ruinous was replaced only by a dangerous ford. The bounds of Gondor were the Isen, and the Gap of Calenardhon (as it was then called). The Gap was watched by the fortresses of Aglarond (the Hornburg) and Angrenost (Isengard), and the Fords of Isen, the only easy entrance to Gondor, were ever guarded against any incursion from the “Wild Lands.”

I can imagine it as a sort of dilapidated pioneer town, where trade merchants and migrants (heavily armed, I would imagine) still occasionally traversed up and down the Greenway.

[Huinesoron]

It looks like what you're remembering is the idea that Tharbad remained inhabited down to 2912. This ultimately goes back to the Tale of Years, which states:

Originally Posted by Tale of Years

2912
Great floods devastate Enedwaith and Minhiriath. Tharbad is ruined and deserted.

This is the aftermath of the Fell Winter, so you can imagine great floods of snowmelt rushing down the Gwathlo (which name, 'Greyflood', evokes exactly that kind of thing; snowmelt rivers are pretty distinctive), breaking the bridge and washing out the last few houses.

As Morthoron says, those inhabitants are nowhere said to be Gondorian. In fact, Unfinished Tales gives us this lovely description:

Originally Posted by Unfinished Tales: Lond Daer

Before the decay of the North Kingdom and the disasters that befell Gondor, indeed until the coming of the Great Plague in Third Age 1636, both kingdoms shared an interest in this region, and together built and maintained the Bridge of Tharbad and the long causeways that carried the road to it on either side of the Gwathló and Mitheithel across the fens in the plains of Minhiriath and Enedwaith.

A considerable garrison of soldiers, mariners and engineers had been kept there until the seventeenth century of the Third Age. But from then onwards the region fell quickly into decay; and long before the time of The Lord of the Rings had gone back into wild fenlands. 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 ruins on dwindling mounds, and a dangerous ford formed by the ruins of the bridge, impassable if the river had not been there slow and shallow - but wide.

The garrison you refer to leaves in the 17th century - almost certainly during the Great Plague, which caused Gondor to pull everything back into the heartland. As Morthoron quotes, the bridge was maintained for another 400 years or so, but ultimately fell into disrepair (and, indeed, into the river). The crossing remained for much longer - the Nazgul actually used it on their way to the Shire! - but it was dangerous.

UT also provides the details that the road approached Tharbad via a causeway, which tells us that the whole area was swampy. Those floods, coming down from the marshes at Swanfleet, must have been absolutely devastating.

hS