The region presently known as the Black Marsh was once part of a much greater landmass within the domain of the Hist, but the greater part of the region was flooded during the wanderings of the humanoid Mer races. The earliest inhabitants of the Black Marsh and environs are believed to have been the Hist, great life-giving trees of unknown capacities. The native Argonians organize themselves on the tribal level with success and efficiency, and are only loosely integrated into the ruling Empire. Foreign agricultural, colonial, and commercial ventures beyond the slave-trade have met with abject failure. The region possesses a tropical climate, lending its plants the capacity to overturn all attempts to cultivate them. Black Marsh is lush and threatening, teeming with poisonous plants and violent predators. Argonians thrive in the foreboding swamps of Black Marsh. An alternate name, Argonia, is also used by the Mer races of the Elder Scrolls series, following the name of an obscure ancient battlefield, and to avoid the negative connotations of the term 'Black Marsh'.
It is presented as the homeland of the reptilian humanoid race of Argonians, and a race of sentient trees known as the Hist. Is a region that is largely covered in dense swamps, and is located in the south-east section of the continent of Tamriel.