The species lived in coastal sand dunes of the Sunset District of the San Francisco Peninsula in California.

The Xerces blue is believed to be the first American butterfly species to become extinct due to loss of habitat caused by urban development.

[10] The loss of the Lotus plant that the butterfly fed on while in its larval stages is believed to be one reason for the extinction of the Xerces blue.

The plant could not survive in the disturbed soils due to human development and was no longer available to the Xerces blue.

The Palos Verdes blue (Glaucopsyche lygdamus palosverdesensis), which is considered a Los Angeles cousin of the Xerces, is being reared in labs.