The King of Arthedain was a title created after the breakup of Arnor into the sub-kingdoms of Arthedain, Cardolan, and Rhudaur in TA 861.

After the death of Eärendur, his three sons quarreled over the succession causing a civil war between them and their respective realms. Amlaith, the eldest son claimed the throne of Arnor but his rule was limited only to the region of Arthedain with its capital in Annúminas near Lake Evendim and then Fornost, while the others founded Cardolan and Rhudaur.

Its kings made several attempts to reunite the kingdom; Argeleb I was even able to exert its authority over Cardolan, but corruption in the kingdoms and war with Angmar prevented any reunification of Arnor. The kingdom and the title ended with the death of Arvedui but his line survived in the Rangers of the North, and being the senior kingdom of the Dunedain their chieftains formed the heirs of Isildur leading up to Aragorn Elessar.

The Kings of Arthedain (TA 861 - TA 1975)
1 Amlaith, eldest son of Eärendur and also tenth King of Arnor TA 861 - TA 946
2 Beleg, son of Amlaith TA 946 - TA 1029
3 Mallor, son of Beleg TA 1029 - TA 1110
4 Celepharn, son of Mallor TA 1110 - TA 1191
5 Celebrindor, son of Celepharn TA 1191 - TA 1272
6 Malvegil, son of Celebrindor TA 1272 - TA 1349
7 Argeleb I, son of Malvegil (claimed the title of King of Arnor) TA 1349 - TA 1356
8 Arveleg I, son of Argeleb I TA 1356 - TA 1409
9 Araphor, son of Arveleg I TA 1409 - TA 1589
10 Argeleb II, son of Araphor TA 1589 - TA 1670
11 Arvegil, son of Argeleb II TA 1670 - TA 1743
12 Arveleg II, son of Arvegil TA 1743 - TA 1813
13 Araval, son of Arveleg II TA 1813 - TA 1891
14 Araphant, son of Araval TA 1891 - TA 1964
15 Arvedui, son of Araphant and last King of Arthedain TA 1964 - TA 1975

After Arvedui the North Kingdom was no more, and the line of Kings continued in the Chieftains of the Dúnedain, the Rangers of the North.