When and why did Aragorn go to Rhun?

[Phantom718]

Was this ever written about beyond one brief mention at the Council of Elrond? Did he travel there when he was hunting Gollum?

 

[Council_of_Gondor]

No I wouldn't say it's described in detail. It happens after Aragorn (under the name Thorongil) stops serving Steward Ecthelion of Gondor. He has just raided Umbar and killed the Captain of the Haven, and a great triumpf as prepared in Minas Tirith to celebrate him, but when the fleet returned to Pelargir he sent a message to Ecthelion and crossed the Anduin. He was last seen looking at the Shadow Mountains of Mordor.

He then travelled into the far East and South "exploring the hearts of men good and evil" and learning about the "plots and devices" of the servants of the Dark Lord. Apparently this paid off in the long run, where his exploits was one of the reasons the West won during the War of the Ring.
I'd assume after he had seen Umbar he might have felt the presence of Evil or something like that. Perhaps he saw that the great white pillar was destroyed.
The timing seems to fit well.
Some history about Umbar in this period:
2885 T.A. Corsairs of Umbat aids Haradrim in claiming Harondor totally. At this point the corsairs would likely have been under Sauron's command, though not something Gondor would know, perhaps.
2951 T.A. Sauron declares himself openly
Around this time the great pillar would likely have been destroyed:
"After the second arising of Sauron, Umbar fell under the domination of his servants and the great white pillar that had been built on the highest hill of the headland above the haven by the followers of Elendil as a monument for the humiliation of Sauron by Ar-Pharazon was thrown down."

"In 2980 Aragorn served steward Ecthelion II as a captain in disguise under the name Thorongil, gathered a small fleet, attacked Umbar by night, burned a great part of the ships of the Corsairs, overthrew the Captain of the Haven in a battle upon the quays and then withdrew his fleet with small losses."
- Tolkiengateway

I think it is likely that Aragorn would have seen the great pillar was destroyed and then have guessed that the Men of Umbar would have been under Sauron's control. And this knowledge motivated him to go East and South to understand these Men and why they decided to serve the Dark Lord.

How this happened or what else he might have done there we do not know. As king him and Éomer fought the Easterlings though, so perhaps his old knowledge about these regions might have aided him - or perhaps he knew some of the Easterlings' weaknesses which insured victory. Once again - just my theory on it. Seems plausible to me.

I think most of the hunting for Gollum happened in Rhovanion, Mirkwood, borders of Mordor and the vales of Anduin.

I hope that's helpful information, my friend

 

[Phantom718]

Yes indeed, thank you

 

[Council_of_Gondor]

Yes indeed, thank you

Could be interesting to cover in an episode on my channel, so thanks for the question!