The web team for the Lord of the Rings Online has published another of their Exploring Middle-earth articles. The focus of this installment is the 'Garth Agarwen'.

Deep in the Lone-lands, a vast marshland stretches across the land, red as the blood that was spilled into its waters during the wars between Arthedain and Rhudaur. The Eglain of Ost Guruth call it the Red Swamp. In the northern reaches of the bog called Agamaur, lie the ruins of an ancient Rhudaurian fortress, now known as Garth Agarwen. Garth Agarwen was one of the chief bastions of the Hill-men of Rhudaur before it fell into decay.

You can read the article here, or here from the European site.