In 1888 the Del Norte County Board of Supervisor's authorized construction of a road from Crescent City south to Requa and the Klamath River. This road was placed under construction in 1889 and was known as the Crescent City-Requa Road. The Crescent City-Requa Road would be completed by 1895 and ascended the notable slope of the Last Chance Slide. Journeys on the Crescent City-Requa Road were made via four horse or six horse teams which took ten to sixteen hours to complete depending on the weather conditions. Fare for a trip on the Crescent City-Requa Road cost travelers a fee of $5 dollars.
Much of the Crescent City-Requa Road was constructed by way of use of Coastal Redwood puncheons. A photo of a derelict segment of the Crescent City-Requa Road can be seen in the March 1934 California Highways & Public Works.
The history of what would become US Route 101 ("US 101") over the Last Chance Grade begins with the approval of the 1909 First State Highway Bond Act. The First State Highway Bond Act was approved by voters during 1910 and was the genesis point of some of the most notable highways in California. Legislative Route Number 1 ("LRN 1") as originally plotted was a new State Highway which was designated between San Francisco north to Crescent City. The route of LRN 1 would be extended to the Oregon State Line during the 1919 Third State Highway Bond Act and was came be known as the Redwood Highway. LRN 1 can be seen aligned over the Last Chance Grade via the Crescent City-Requa Road on the 1917 California State Automobile Association Map.
The existing Crescent City-Requa Road was upgraded and modernized to State standards by 1920. Much of the previous Redwood puncheon roadway from Crescent City south to Wilson's Creek was abandoned as it was not suited to automotive traffic. This 1920 alignment of LRN 1/Redwood Highway now exists as Enderts Beach Road and the California Coastal Trail in Del Norte Coast Redwoods State Park. LRN 1 and the Redwood Highway can be seen aligned over the Last Chance Grade between Crescent City-Requa on the 1920 Clason Highway Map of California.
In November 1926 the US Route System was created. US Route 101 from San Francisco north to Crescent City was aligned over the Redwood Highway. Both US 101 and the Redwood Highway between Crescent City-Requa can be seen on the 1927 Rand McNally Highway Map of California.
The March 1934 California Highways & Public Works describes the nearly completed realignment of US 101 and the Redwood Highway south of Crescent City. Specifically new alignment of US 101/Redwood Highway would eliminate 205 curves south of Crescent City to the Last Chance Slide. The new alignment of US 101 was cited to have only 34 curves which shortened the distance between Crescent City and the Last Chance Slide from 10.31 miles to 9.52 miles. The article cites the new alignment of US 101 and the Redwood Highway as having expected completion date by late 1934. Note; the history of the Crescent City-Requa Road can be found in the March 1934 California Highways and Public Works.
The September 1935 California Highways & Public Works features the formal dedication of the US 101/Redwood realignment south of Crescent City to the Last Chance Slide. The formal dedication ceremony took place on August 18th, 1935.
The 1935 California Division of Highways Map of Del Norte County displays the new alignment of US 101 south of Crescent City to the Last Chance Slide alongside the 1920 alignment.
Since 1935 US 101 and the Redwood Highway have changed minimally. The climb via the Last Chance Grade still has the signature vista of Crescent City described in the September 1935 California Highways & Public Works and serves as a boundary of the Redwood National Park & State Parks system.
According to CAhighways.org from July 2012 to February 2013 the Last Chance Grade experienced over 200 slides. The road deck of US 101 subsequently slid 13 inches horizontally and 10 inches vertically. In March 2014 Caltrans established the Last Chance Grade Partnership to work with local authorities on the feasibility of realigning US 101 off the Last Chance Grade. As of 2019 Environmental studies have been continuing to progress regarding potential realignments of US 101. This image snip from CAhighways.org shows the multiple alignments under study from Postmile DN 19.81 south to DN 13.47.