Conejo Grade

The surrounding area was formed by volcanic eruptions millions of years ago, a rare geological formation in Southern California.

The grade experienced improvements by the newly established State Highway Department in 1912, when the road measured six miles (9.7 km) long and had 49 curves.

[5] Early European settlers in the Conejo Valley, known as the Norwegian Colony, needed a safe way to move bales of hay and sacks of wheat and barley to the Hueneme Wharf on the Oxnard Plain.

By 2017, the National Park Service has recorded a dozen mountain lions struck and killed by motorists on this section of freeway since 2002 when they began the study.

[13] The Woolsey Fire started the same day, closed the freeway near Oak Park, grew to over 98,362 acres (39,806 hectares), destroyed an estimated 616 structures, and killed 3 people.