Ngaremlengui, possessing the largest land area with over 68 square kilometers, is the largest state in the Palauan archipelago. It is located on the north-central west coast and is bordered by five states: Ngatpang on the south, Ngardmau on the north, Ngiwal on the northeast, Melekeok on the east and Ngchesar on the southeast.

Ngaremlengui terrain is varied in its make up and includes: some of the highest hills in Palau including Badechemetel along the west coast between the inlet to Ngeremeduu Bay and Chomet ubet River; the Ngermeskang River, the longest in Palau, in the south; rolling hills, with elevations of 250 meters, near the border with Ngardmau; heavy fringes of mangrove swamp forest along the Ngermeskang and Ngerbechederngul rivers in the northeast corner of Ngeremeduu Bay and along the northern coast; and large area of savanna with patches of forest which cover most of the interior or the state.

Inhabitated villages includes: Ngermetengel, located on the northern side of Chometubet; Imeong, located a short distance to the northeast on the Imeong River; and Ngchemesed, on the north shore of Ngeremeduu Bay.

With over 40 traditional village sites, Ngaremlengui clearly played an important part in Palau's past. In the oral history of Palau, Ngaremlengui is said to be one of the four children of Milad and one of the four cornerposts of Palauan society. It is also said that Milad gave birth to the children of Roismlengui, therefore the terrain feature holds an important place in Palauan mythology and is closely connected with traditional religious beliefs.

The Uluang Terraces are considered to be the most important archaeological site in Ngaremlengui. Ngaremlengui also holds what is reported to be the largest of the Japanese colonial era plantations, Ngermeskang Plantation. A substantial number of structural remains are still present at this site, along with a monument which overlook the old factory area.