ArmenelosArmenelos - The race of Men (Edain) who would become the Númenóreans in the Second Age departed Middle Earth and sailed to a land prepared for them by the Valar.  It was a large island in the middle of the Sundering Sea, and they were led by a star (Rothinzil) which stood alone in the Western sky.


"Then the Edain set sail upon the deep waters, following the Star, and the Valar laid a peace upon the sea for many days, and sent sunlight and a sailing wind, so that the waters glittered before the eyes of the Edain like rippling glass, and the foam flew like snow before the stems of their ships.  But so bright was Rothinzil that even at morning Men could see it glimmering in the West, and in the cloudless night it shown alone, for no other star could stand beside it.  And setting their course towards it the Edain came at last over leagues of sea and saw afar the land that was prepared for them, Andor, the Land of Gift, shimmering in a golden haze.  Then they went up out of the sea and found a country fair and fruitful, and they were glad.  And they called the land Elenna, which is Starwards; but also Anadûnê, which is Westernese, Númenórë in the High Eldarin tongue." ~The Silmarillion (Akallabêth)


The Númenóreans were unique among Men in that they had Elven blood mingled with their own as a result of Elros, the Half-elven, choosing a mortal life and becoming their first king.  Because of this, they were fairer and longer-lived than other Men of Middle Earth.


"This was the beginning of that people that in the Grey-elven speech are called the Dúnedain: Númenóreans, Kings among Men.  But they did not thus escape from the doom of death that Ilúvatar had set upon all Mankind, and they were mortal still, though their years were long, and they knew no sickness, ere the shadows fell upon them.  Therefore they grew wise and glorious, and to all things more like to the Firstborn than any other of the kindreds of Men; and they were tall, taller than the tallest of the sons of Middle-earth..." ~The Silmarillion (Akallabêth)


And they built for themselves a glorious city which became their capital.


"...and hard by upon a hill was Armenelos, fairest of cities, and there stood the tower and the citadel that was raised by Elros, son of Eärendil, whom the Valar appointed to be the first king of the Dúnedain." ~The Silmarillion (Akallabêth)


"The land of Númenor resembled in outline a five-pointed star, or pentangle, with a central portion some two hundred and fifty miles across, north and south, and east and west, from which extended five large peninsular promontories...The central portion was called Mittalmar (Inlands), and it had no coast, except the land about Rómenna and the head of its firth.  A small part of the Mittalmar was, however, separated from the rest, and called Arandor, the Kingsland.  In Arandor were the haven of Rómenna, the Meneltarma, and Armenelos, the City of the Kings; and it was at all times the most populous region of Númenor." ~Unfinished Tales (A Description of Númenor)