The last remnants of the ancient realm of
Numenor who came to Middle-earth after
Numenor's destruction.
The Dunedain were descendants of
Elrond's brother Elros, who chose to be counted
amond Men, rather than Elves since he and Elrond are half man/half elf. Since Elros was half Elf, he lived three times longer than normal men, and died at the age of 500.
Since the Dunedain were descendants of he, they had the same long life. But after comming to Middle-Earth and mating with the humans already there, their long life diminished. However some still retained the gift of long life. Aragorn was 87 at the time of Lord of the Rings, and died at the age of 210.
Aragorn is one of the Dunedain, the last
remnants of
Numenor.