Circle Ranch is a ‘Sky Island’ May 26, 2010 Chris Gill The Sierra Diablo range rises one-half mile above the Chihuahuan Desert floor in Hudspeth County Texas, 40 miles below the New Mexico line. It is well within the theoretical range of Guadalupe Mountain elk. Share on Facebook Share on Twitter Share on LinkedIn Previous Next Author: Chris Gill Ranching, wildlife management, finance, oil & gas, real estate development and management.