See text Hesperocyparis (western cypress)[1] is a genus of trees in the family Cupressaceae, containing North American species otherwise assigned to the genus Cupressus.

Members of Hesperocyparis were and still are placed in Cupressus by many authorities, but phylogenetic evidence supports a different affinity.

A 2021 molecular study found Hesperocyparis to be the sister group to the genus Callitropsis (containing only the Nootka cypress), with this clade being sister to the Asian genus Xanthocyparis, containing only the Vietnamese golden cypress.

[3] If Hesperocyparis and the other smaller genera were reunited with Cupressus it may also require them to be merged into a larger genus including Juniperus.

[7] There is disagreement about this classification, with some scientists continuing to use Cupressus in preference to Hesperocyparis.