The earliest historical trail remnant of Montara Mountain is the precolonial Indian Trail which traverses the ridgeline between Willow Brook Estates towards Saddle Pass following the high ridgeline above Green Valley and winding down towards Martini Creek.

The earliest descriptions of the area are from the Portolá Expedition in 1769, "We halted near the shore, along which the passage was entirely closed by a steep hill, at the foot of which ran a stream of good water.

Many deer have been seen upon the hills here... Bear tracks and droppings have been seen...our sick men since we left the creek of La Salud (Waddell Creek in Santa Cruz County) have been improving more every day..."[5] They had descended the treeless hill and pitched camp in the middle of a small valley (San Pedro).

This road which routed closer to the ocean and Devil's Slide terminated in Shamrock Ranch and persisted until 1915.

[6] Due in part to its biologically isolated location near the end of a peninsula, the mountain has an extensive and unique biodiversity, especially on the serpentine soils of the lower slopes.

A number of plant endangered species are found on this mountain, including Hickman's potentilla and San Mateo thornmint, Acanthomintha duttonii.