In the fictional universe of J. R. R. Tolkien, Tar-Ardamin is sometimes listed in the list of rulers of Númenor but is sometimes omitted. He was the son of King Tar-Calmacil, and if he is counted as one of the rulers, then he is the 19th in the line of rulers.
His son, Ar-Adûnakhôr, is generally counted as the 20th ruler.