I. i. missionensis is federally endangered and found in only a few locations. Its habitat is restricted to the San Francisco Bay Area, specifically six areas, the Twin Peaks area in San Francisco County, Fort Baker, a former military installation managed by the National Park Service (NPS), in Marin County, the San Bruno Mountain area in San Mateo County, the Marin Headlands, in Golden Gate National Recreation Area (another NPS entity), Laurelwood Park and Sugarloaf Open Space in the city of San Mateo, and Skyline Ridge, also in San Mateo County. San Bruno Mountain hosts the largest population of Mission blues, a butterfly commonly found around elevations of 700 feet.
The text describes the restricted habitat of the endangered missionensis species within the San Francisco Bay Area. It highlights the specific locations where this species is found and mentions that San Bruno Mountain has the largest population of Mission blues, a butterfly commonly found at elevations of 700 feet.