The following names were used by the highway department:

Route 1, Sausalito to Crescent City
Route 1, Crescent City to Oregon
Route 2, San Francisco to San Diego
Route 3, Sacramento to Oregon
Route 4, Sacramento to Los Angeles
Route 5, Stockton to Santa Cruz
Route 6, Sacramento to Davis
Route 7, Benicia to Red Bluff
Route 8, Novato to Fairfield
Route 9, San Fernando to San Bernardino
Route 10, Hanford to Visalia
Route 10, San Lucas to Hanford
Route 10, Visalia to Sequoia Park
Route 11, Sacramento to Nevada
Route 12, San Diego to El Centro
Route 13, Salida to Sonora
Route 13, Sonora to east of Sonora Pass
Route 14, Oakland to Martinez
Route 15, Ukiah to Emigrant Gap
Route 16, Hopland to Lakeport
Route 17, Roseville to Nevada City
Route 18, Merced to Mariposa
Route 18, Mariposa to Yosemite Park
Route 19, west of Claremont to Riverside
Route 20, Weaverville to Redding
Route 20, Arcata to Weaverville
Route 21, Richvale to Oroville
Route 21, Oroville to Quincy
Route 22, north of Hollister to San Juan Bautista
Route 23, Saugus to Sauth Lake Tahoe
Route 24, Lodi to southeast of Markleeville
Route 25, Nevada City to Downieville
Route 26, San Bernardino to El Centro
Route 27, El Centro to Arizona
Route 28, Redding to Nevada
Route 29, Red Bluff to Nevada
Route 31, San Bernardino to Nevada
Route 32, Chowchilla to Gilroy
Route 33, Bakersfield to Paso Robles
Route 34, Galt to southeast of Luther Pass
Route 35, Mad River to Peanut
Route 36, Downieville northwest
Route 37, Auburn to Truckee
Route 38, South Lake Tahoe to Nevada
Route 39, Tahoe City to Nevada
Route 40, west of Chinese Camp to Lee Vining
Route 41, General Grant Grove to Kings Canyon
Route 42, Saratoga Gap to Redwood Park
Route 43, Waterman Canyon to Big Bear Lake
Route 44, Boulder Creek to Redwood Park
Route 45, Biggs to Willows
Route 46, north of Yreka to Klamath
Route 47, Orland to Chico
Route 48, Cloverdale to Albion
Route 49, Calistoga to north of Lower Lake
Route 50, northeast of Lower Lake to Rumsey
Route 51, Santa Rosa to Sonoma
Route 52, Tiburon to Mill Valley
Route 53, Fairfield to Lodi
Route 54, east of Sloughhouse to Plymouth
Route 55, San Francisco to north of Santa Cruz
Route 56, Cambria to Carmel
Route 57, Santa Maria to Freeman Junction
Route 58, Mojave to Arizona
Route 59, Gorman to Lancaster
Route 60, El Rio to San Juan Capistrano
Route 61, La Canada Flintridge to Red Box Gap
Route 62, Azusa to San Gabriel Canyon
Route 63, Big Pine to Oasis
Route 64, Mecca to Blythe
Route 65, Auburn to Sonora
Route 66, Lathrop to Manteca
Route 67, San Juan Bautista to Chittenden
Route 68, San Francisco to San Jose
Route 69, San Rafael to Point San Quentin
Route 70, Ukiah to Mendocino State Hospital
Route 71, Crescent City to Oregon

This comes from the Assembly Journal, as follows:

  • 1931 pp. 796-797

And other sources: