Hesperelaea palmeri was found only on Guadalupe Island, a small island in the Pacific Ocean, part of the Mexican state of Baja California, about 400 km (250 mi) southwest of Ensenada.

[3] At the time of the collection of the type material in 1875, Hesperelaea palmeri was found only in a single canyon on the east side of the island.

[4][5] Phylogenetic analyses based on DNA from the nuclear genome as well as mitochondrial and chloroplast DNA suggest that H. palmeri is closely related to the genera Forestiera and Priogymnanthus in tribe Oleeae, and perhaps the sister lineage of Forestiera.

[6][7] A molecular clock analysis estimated its divergence from its closest relatives in the Early Miocene, likely pre-dating the age of Guadalupe Island.

This suggests that H. palmeri is a paleoendemic that was once more widespread and then retreated to Guadalupe Island following environmental change.