Lange’s metalmark butterfly (Apodemia mormo langei) is a federally endangered species that is currently only known to occur at Antioch Dunes National Wildlife Refuge in Contra Costa County, California. Lange’s metalmark is a subspecies of Mormon metalmark butterfly (Apodemia mormo), a species that tends to use native buckwheat species in the genus Eriogonum as its hostplant. The Lange’s metalmark population at Antioch Dunes has been declining since the late 1990’s, and in recent years has been precariously close to extinction. This presentation provides an overview of Lange’s metalmark natural history, and the actions U.S. Fish and Wildlife Service has been taking to conserve this species. These actions include: working with our partners and external experts to monitor the population status and trends of Lange’s metalmark; conducting habitat restoration and enhancements; conducting invasive plant control; preventing wildfires; reducing air pollution and trash; head-starting and captively propagating Lange’s metalmark; seeding and out-planting of the Lange’s metalmark hostplant, Antioch Dunes buckwheat (Eriogonum nudum var. psychicola); and performing research aimed at filling key knowledge gaps, such as understanding the behavior of male and female butterflies and developing an improved understanding of the conservation genomics of this and nearby populations of Mormon metalmark.