Old Spanish Trail Main Route as it is known is neither old nor
Spanish nor a trail.
It was first traveled and explored by a group of Americans, under the
leadership of William Wolfskill in the fall of 1830. With
him on this passage was George C Yount, the northern California town of
Yountville was named for him. On this trek too was Francis Ziba Branch.
of note to those of us on the Central Coast, Branch settled along the
Arroyo Grande Creek and was granted the Santa Manuela Rancho land
grant. A curious twist of history, the founder of Arroyo Grande helped
pioneer the Old Spanish Trail. Their interest was in trapping
beaver in Califorinia's Sierra Nevada and in gathering horses to take
back to Santa Fe. Wolfskill, Branch and Yount stayed in CA, tried
their hand at hunting otters, but, that did not pay off.
The trail was named the Old Spanish trail by Captain John C. Fremont, who, as with so many things got it wrong.
Rather than upset the whole applecart by trying to retitle a trail that has been known by Old Spanish Trail since Fremont wandered through. I think we can justify calling it simply, The Spanish Trail. That is a little easier to roll off the tongue.