Part 1; the history US Route 101 and California State Route 198 in San Lucas
The modern site of San Lucas was named in honor of Rancho San Lucas of Mexican Alta California. Rancho San Lucas was granted to José Rafael Estrada during 1842 who in turn sold it James McKinley during 1843. Following the Mexican American War, the property claims of the Mexican Ranchos were honored by the American Government which led to Rancho San Lucas being retained by James McKinley. Rancho San Lucas would be sold to Alberto Trescony during 1863 which was later consolidated into a 20,000-acre cattle ranch with nearby Rancho San Bernardo and Rancho San Benito.
By 1886 the Southern Pacific Railroad was extended southward from Soledad through Rancho San Lucas. The Southern Pacific Railroad established a railroad siding which took the name of "San Lucas" in honor of the property donated by Alberto Trescony. By 1887 Post Office service was transferred from nearby Griswold and has remained operating ever since.
Salinas Valley was ultimately part of the American El Camino Real which began being signed as an Auto Trail starting in 1906. The era of State Highway Maintenance through Salinas Valley would ultimately begin with the 1909 First State Highway Bond Act which was approved by voters in 1910. One of the highways approved through the 1909 First State Highway Bond Act was a 481.8-mile highway originating at the City Limits of San Francisco which terminated in San Diego. This highway would ultimately come to be known in time as Legislative Route Number 2 ("LRN 2"). Within Salinas Valley much of LRN 2 would follow the existing corridor along the frontage roads of the Southern Pacific Railroad which included the community of San Lucas.
1915 Legislative Chapter 404 extended LRN 10 from Hanford west to San Lucas via the road through Warthan Canyon. Early LRN 2 and LRN 10 can be seen intersecting in San Lucas on the 1917 California State Automobile Association Map. LRN 2 is shown following two at-grade crossings of the Southern Pacific Railroad onto Main Street in San Lucas. LRN 10 is shown terminating at LRN 2 in San Lucas via Mary Street.
The January 1915 California Highway Bulletin references surveys for the location of LRN 2 as being completed branching north and south from San Lucas.
As part of the 1964 California State Highway Renumbering the Legislative Route Numbers were dropped. Thusly both US Route 101 and California State Route 198 were both assigned as the legislative highway designations through San Lucas. California State Route 198 can be seen with a western terminus point in San Lucas on the 1964 Division of Highways Map.
The May/June 1965 California Highways & Public Works featured the realignment of US Route 101 between Bradley and San Ardo. The article goes onto to describe the numerous upcoming projects to realign US Route 101 to a freeway grade between San Ardo north to King City. Right of way acquisition to realign US Route 101 and California State Route 198 is stated to be planned to commence during 1965.
The July/August 1965 California Highways & Public Works announced the location of a 1.1-mile realignment of California State Route 198 to the planned US Route 101 freeway in San Lucas had been selected at the May/June California Highway Commission meetings.
The planned realignments of US Route 101 and California State Route 198 near San Lucas appear on the 1967 Division of Highways Map.