A BLM National Byway which climbs to the top of 5,681-ft.  Harquahala Peak, the highest mountain in southwestern Arizona.  At the top are 2 small parking areas with picnic tables.  A hiking trail with information kiosks goes to an old 1920's observatory. Rating: Easy: it gets a bit narrow, steep and rough at the top but any 4WD SUV with low range can make it.