Everfrost caves.
 

There are caves at the end of the west branch of the river in everfrost.
How do I get in there?

I believe you have to drop down through a hole in the ice and swim.

But I'm not 100% sure

I think that is correct. I remember struggling on this trying to finish that Cleric temple of ro armor set.

Yep miragul and some skeletons back there.

Don't drown!

Are you talking about the underwater stuff op?

This, exactly. Make sure you have Enduring Breath of some sort; you won't survive without it, even with 200 swimming.

There's an item that's part of the Paladin spell Divine Might quest on the ground in those caves.

The hole in the ice is kinda close where Megan OReilly roams towards the river. The swim ain,t too bad distance if your skilles are ok. GL ��

-Rebro