This is not Reavis Ranch Trailhead (southern most or otherwise).  The official name of this trailhead is Rogers Trough Trailhead.  

It is true that this trail head is on a portion of Reavis Ranch Trail #109, but that doesn't make it the name of the trailhead.

There is a Reavis Trailhead on the north end of the Reavis Ranch trail #109 and labeling this as "Reavis Ranch Trailhead" just creates confusion.