While previous phylogenies found Tsuga to be separated into Asian and American clades, recent phylogenomic work has produced a much more resolved and nuanced picture of Tsuga relationships. A recent study based on an analysis of 881 nuclear genes plus data from 60 plastid and 23 mitochondrial loci claims that the genus most likely originated in North America. Some members of the genus then later spread from North America to East Asia via the Bering Land Bridge.

Tsuga appears to comprise two clades, one containing the Western North American