U.S.A., South Dakota, Harding, Custer National Forest: Slim Buttes: in the vicinity of Rimrock Spring, ca 1 air mi S of Forest Road 3151, ca 7.5 air mi SE of Summit Pass on SD Hwy 79 and ca 31 air mi SE of Buffalo.
45.3151 -103.0373 NAD 83
45.3151° N, 103.0373° W; NAD 83, , GPS reading; T16N R9E S28 SW1/4; also N1/2 S33