Enedwaith, also spelled Enedhwaith, originally referred to both a region of Middle-earth and the men that inhabited it, although the region Enedwaith retained that name even when the Enedwaith people were no more.
The boundaries of the Enedwaith, which is Sindarin for 'Middle-region' as well as 'Middle-folk', were defined in the north by the rivers Gwathló and Glanduin, to the east by the Hithaeglir, and to the west by Belegaer, 'The Great Sea'. The southern border was less clear, but was probably formed by the river Isen.
The Enedwaithrim themselves "were forest dwellers, scattered communities without central leadership." They were distantly related to the Haladin of old, but this wasn't recognized in time by Númenóreans, who were mainly descended from the First and Third Houses of the Edain, and therefore spoke a language which was not related. The Enedwaithrim were not ranked as Middle Men, friends and distant kin of the Edain, but were ranked among the "people of darkness", enemies and aliens.
The denuded forests of Enedwaith, and much of those to the north in Eriador, were finally destroyed by the War of the Elves and Sauron around 1700 S.A., during which much of what had survived the felling was burnt. Only remote corners like Eryn Vorn survived in Eriador, and the Old Forest still further north. Many surviving natives took refuge in the eastern highlands of Enedwaith, "the foothills of the Misty Mountains", which ultimately became Dunland.
After S.A. 3320, Enedwaith formed the most northern part of the new Kingdom of Gondor, at least officially. The south-east was still "in places well-wooded", but elsewhere Enedwaith was by this time "mostly grassland." Following the Great Plague in T.A. 1636 however, Gondors authority permanently lapsed throughout the region.
Tharbad, originally one of two ancient cities on the Gwathló, and the only one to survive beyond the early Third Age, was finally abandoned following devastating floods in 2912 T.A., and thereafter, only two groups survived in Enedwaith: the Dunlendings in the far east, and a "fairly numerous but barbarous fisher-folk" wandering the coast.