US 99 – Three Mile Grade

Virtual Tour of US 99
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Three Mile Grade / Oak Flat

Three Mile Grade at the Oak Flat Ranger Station.
Three Mile Grade at the Oak Flat Ranger Station.

Three Mile Grade goes between Frenchman’s Flat to Whitaker Summit. The Oak Flat Ranger Station has been a stop along this highway for a long time. Here, campgrounds and water are available for use to the public. This is about half way down Three Mile Grade. As a side note, Oak Flat was formed when a large portion of the mountain above slid down many thousands of years ago.

View of Three Mile Grade and I-5 from the Ridge Route.
View of Three Mile Grade and I-5 from the old Ridge Route.
Three Mile Grade in 1970. Note the still intact four lane striping and original divider. Photo Courtesy- Gordon Glattenberg
Three Mile Grade in 1970. Note the still intact four lane striping and original divider. Photo Courtesy- Gordon Glattenberg
Looking south along Three Mile Grade near the bottom.
Looking south along Three Mile Grade near the bottom.
Three Mile Grade in 1958, looking south toward Castaic above Piru Gorge.
Three Mile Grade in 1958, looking south toward Castaic above Piru Gorge.

Go North on US 99 to Bakersfield

Go South on US 99 to Los Angeles

Return to US 99 Introduction

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