#parallels!!!!

First off, they were born in the same year. If you look at the (sparse and rather unreliable) data we have on timelines for when other elves who are considered of the same generation are born, this is VERY uncommon. The only time it happens again is Aredhel and Galadriel, iirc, and I haven't had the time or energy to unpack any narrative parallels they might have as of yet.

Then, of course, we have very little information about their time in Valinor except that they were besties. Which makes sense. We DO know, however, that they both fell in love with Vanyarin women, Elenwe and Amarie, and lost them during the Flight of the Noldor. Elenwe dying during the crossing of the Helcaraxe, and Finrod leaving Amarie behind. Finrod and Amarie were seperated because she didn't follow him, and Turgon and Elenwe were seperated because she did.

After arriving in Beleriand, Finrod builds Minas Tirith and Turgon builds Vinyamar. It's been a while since I've reread the silm, so I actually don't remember a whole lot of details about Vinyamar. But my big point here is that Minas Tirith is on Tol Sirion on the river Sirion, and Vinyamar faced the sea. Both cities were strongly associated with bodies of water. There's also an interesting contrast in their fates. While Vinyamar was never touched by Morgoth or his servants, Minas Tirith eventually become Tol-in-Gaurhoth, the fortress of Sauron. Vinyamar was also an important location for Tuor, and Tol-in-Gaurhoth became an important location for Beren, both of whom ended up marrying elvish princesses of hidden realms.

Of course, there's the most obvious connection, with them both being given a dream by Ulmo instructing them to build hidden strongholds, after which they leave their original cities to build new ones. They also both have a tendency to take in and befriend mortal men. Húrin and Huor for Turgon and Beor, Barahir, and Andreth for Finrod. They were also both rescued from almost certain death in battle by said mortal men

And then we've got the stories of their deaths and the ruin of their cities. While these don't match up chronologically, they do have a LOT of parallels.

They both took in a nephew after one of their siblings died. Orodreth and Maeglin. Orodreth is trying desperately to fill Finrod's role, while Maeglin wants to undermine Turgon. Both stories heavily involve the influence of a mortal man who was close to the king. Also, Maeglin's and Turin's influence over Turgon and Orodreth, respectively, cause the kings to ignore the advice of even their most trusted advisors against their better judgement. Ultimately, both are destroyed.

Their deaths are also, like, not quite mirror images of each other. Finrod, who spent his time in Beleriand making friends, died with only one other person by his side, in a dungeon deep underground, because he was trying to help along what becomes one of the greatest love stories in Middle Earth. Turgon, who spent all his time in Beleriand hiding away, died surrounded by people who refused to leave him, in a high tower, because of Maeglin's love turned to darkness. They were both betrayed by family members they had taken in (Celegorm, Curufin, and Maeglin), and died in the towers they built.

Turgon's legacy is deeply entwined in the fate of Middle Earth through Idril and her descendants, while Finrod ultimately leaves very little behind. However, they both have massive lasting impacts on the Edain of Numenor. Especially the royal family, with the Kings of Numenor, Arnor, and Gondor being descended from Turgon, and the Ring of Barahir being passed down as an heirloom and symbol of the kingship (at least when they want to be associated with the eldar).