United States, California, Modoc, Modoc Plateau; Big Valley; Ash Creek Wildlife Area; ca. 5.7 air-miles northeast of Bieber, ca. 7.6 air-miles west of Adin, ca. 1.5 air-mile southeast of Pilot Butte summit, meadow at northern edge of Ash Creek Floodplain (Big Swamp) at southeast base of Pilot Butte. T39N R08E S30 NE1/4 USGS Quadrangle: Big Swamp 1:24,000