Anderson Mountain is on BLM land but is surrounded by a checkerboard of BLM, NM State and private lands. Easiest access is from the west but county roads shown on maps have been privatized thus cutting off access. I came in from the east, from NM-81 to Young Ranch Rd (CR-C016) then onto Cottonwood Rd. Cottonwood Rd ends at a gate near a ranch that sits below Gillespie Mtn. As you near the ranch you will pass a no trespassing sign so best to stop and park on NM State trust lands. Gillespie Mtn is to the west and Anderson Mtn is to the northwest. I ended up hiking three other peaks in the area besides Anderson so I've somewhat adjusted the time/distance to make allowances for my detours even though they were more or less along the way.