US 97 is shown to be realigned to the California State Line south of Klamath Falls to LRN 72 on the 1934 Oregon State Highway Department Route Descriptions (courtesy Johnathan Ledbetter).
According to the Oregonian the original alignment of US 99 over Siskiyou Pass via the grade of the Pacific Highway (Pacific Highway #1) became inadequate to meet the needs of modern highway traffic by the time the 1930s began. This led to a new alignment for US 99 between Ashland to Sikiyou Pass being plotted out. The first segment of this new alignment of US 99 from Ashland to Wall Creek broke ground in October of 1933. This new alignment of US 99 may have been part of the reasoning of why US 97 was shifted to a new terminus in Weed, California during 1934. The 1935 Goshua West Coast Road Map shows US 97 shifted off it's original route to California and being replaced with Oregon Route 66 over Green Springs Highway #21.
The 1935 Gousha Oregon Map shows the shift of US 97 and the newly designated Oregon Route 66 in greater detail.
The 1935 Division of Highways Map of Siskiyou County shows the initial alignment of US 97 on LRN 72. The original alignment of US 97 can be observed entering California via Dorris southward. From Dorris US 97 passed through Macdoel and Mount Hebron southward via Old State Highway towards Bray. From Bray US 97 traveled westward on Forest Route 8001, Forest Route 44N25, and over Butte Creek via Tenant Road. US 97 followed Alder Creek Road and Deer Creek Mountain Road where it joined the modern highway alignment at the siding known as Cougar. Notably all the communities described were Southern Pacific Railroad siding which were largely plotted out circa 1907 when a line was being built Weed and the Oregon State Line. Existing LRN 72 and early US 97 in California were essentially an overlay of the Southern Pacific Railroad frontage facilities.
Thusly, California Legislative Chapter 1402 was approved by the Governor on July 15th, 1965. Legislative Chapter 1402 extended US 97 south through downtown Weed via Weed Boulevard to the Interstate 5 at Highway Avenue Interchange. Legislative Chapter 1402 also created California State Route 265 which was routed north from US 97 via Weed Boulevard to the North Weed Interchange of Interstate 5.
Former US 99 can be followed north from the modern Oregon Route 273/Oregon Route 66 junction into Emigrant Lake. When the waters of Emigrant Lake are low one can still find the original US 99/US 97 junction. US 97 entered Emigrant Lake via what is now Old Green Springs Highway.
The original Emigrant Creek Reservoir was constructed in 1924. The Bureau of Reclamation later expanded the Emigrant Creek Reservoir in 1960 which consumed the original US 99/US 97 junction. The Google Earth image below depicts the original US 99/US 97 junction at the bend in Hill Creek located in the Emigrant Lake Reservoir.
Part 3; exploring the second and third southern terminus points of US Route 97 in Weed, California
From Interstate 5 northbound former US 99 on Weed Boulevard can be accessed via Exit 747 to US 97. Approaching Exit 747 Interstate 5 northbound traffic is notified that US 97 is also Historic US 99. Exit 747 serves as the modern southern terminus of US 97.
US 97 traffic is advised Bend and Klamath Falls in Oregon are the primary Control Cities from Weed. As US 97 begins it is co-signed with Interstate 5 Business. US 97 between Interstate 5 Exit 747 and California State Route 265 on Weed Boulevard carries supplemental "L" suffixed Postmiles given it was extended after 1964.
The Weed Souvenir Shop can be found at the corner of Weed Boulevard and Boise Street at US 97 Postmile SIS L0.144. The Weed Souvenir Shop sells numerous trinkets which are popular with travelers who are entertained by the City Name. The City of Weed is named after after it's founder Abner Weed. In the 19th Century Abner Weed noted that the winds near the present site of the City of Weed were especially good for drying lumber. In 1897 Abner Weed purchased the Siskiyou Lumber & Mercantile Mill in addition to 280 acres of land where the City of Weed now stands. The community of Weed was plotted along the Central Pacific Railroad Line between the communities of Edgewood and Mount Shasta City. The lumber mill at Weed led to the community growing rapidly during the early 20th Century. In 1961 Weed incorporated as a City.
US 97 northbound on Weed Boulevard carries numerous Historic US 99 shields.
US 97 continues on Weed Boulevard until splitting away towards Oregon at the California State Route 265 junction at Postmile SIS L0.43. North of CA 265 the Postmiles of US 97 reset to 0. The junction of US 97 and California State Route 265 serve as the 1934 southern terminus of the highway at what was US 99.
Part 4; US Route 97, Mount Shasta and the Volcanic Legacy Scenic Byway
At approximately Postmile SIS 19.000 the Mount Shasta View Point can be found on US 97 north of Weed. The entirety of US 97 in California part of the Volcanic Legacy Scenic Byway in California The photo below was taken during May of 2014 from the Mount Shasta View Point when the 14,179 stratovolcano was fully visible.