The orchid is endemic to chaparral, coastal sage scrub, and oak woodland habitats.

It is found in the Santa Monica Mountains, Simi Hills, and San Gabriel Mountains of the Transverse Ranges; Santa Catalina Island and San Clemente Island of the Channel Islands, and the Santa Ana Mountains and Cuyamaca Mountains of the Peninsular Ranges.

[1] Platanthera cooperi grows erect to about 90 centimetres (35 in) in maximum height from a bulbous caudex.

The basal leaves are up to 20 centimeters long by 3 cm wide.

The upper part of the stem is a spikelike inflorescence of many small green flowers, which are honey-scented in the evenings.