The Organ Mountains are a rugged mountain range in southern New Mexico in the southwestern United States. They lie 10 miles (16 km) east of the city of Las Cruces, in Dona Ana County.[1] The Organ Mountains are near the southern end of a long line of mountains on the east side of the Rio Grande's rift valley. The range is nearly contiguous with the San Andres Mountains to the north and the Franklin Mountains to the south, but is very different geologically.