Darreh Yas (Persian: دره ياس, also Romanized as Darreh Yās; also known as Rūd Vār and Rūdwār) is a village in Mashayekh Rural District, Naghan District, Kiar County, Chaharmahal and Bakhtiari Province, Iran. At the 2006 census, its population was 329, in 76 families.