California - Criteria: C (architecture/engineering)
| Simmons, William Adam, House |
| Simon's, M. H., Undertaking Chapel |
| Simpson-Vance House |
| Sinatra, Frank, House |
| Singer Building |
| Smiley Park Historic District |
| Smith, Ernest W., House |
| Smith Estate |
| Smith-Tuthill Funeral Parlors |
| Smith, Williams, House |
| SMUD Headquarters Building |
| Snow Creek Ski Hut |
| Sonoma Grammar School |
| Sonoma Plaza |
| Sonoma State Home-Main Building |
| Sonoma Valley Woman's Club |
| South Berkeley Community Church |
| South Bonnie Brae Tract Historic District |
| Southern California Gas Company Complex |
| Southern Counties Gas Co. |
| Southern Hotel |
| Southern Pacific Depot |
| Southern Pacific Depot |
| Southern Pacific Depot |
| Southern Pacific Passenger Depot |
| Southern Pacific Railroad Bayshore Roundhouse |
| Southern Pacific Railroad Company's Sacramento Depot |
| Southern Pacific Railroad Depot, Whittier |
| Southern Pacific Railroad Station |
| Southern Pacific Train Depot |
| South Hall |
| South Marengo Historic District |
| South of Campus Neighborhood |
| South San Francisco Opera House |
| South Serrano Avenue Historic District |
| Southwest Museum |
| Sovereign Hotel |
| Sowden, John, House |
| Space Flight Operations Facility |
| Spencer, John, House |
| Sperry Office Building |
| Sperry Union Flour Mill |
| Spillman Engineering 3-Abreast Carousel |
| Spreckels Theatre Building |
| Spring Street Financial District |
| Spurgeon Block |
| Squire, John Adam, House |
| S.S. CATALINA |
| SS Red Oak Victory (victory ship) |
| SS RIO DE JANEIRO Shipwreck |
| SS WINFIELD SCOTT (Steamship) |
| Stadtmuller House |
| Stage Stop |
| Standard Oil Building |
| St. Andrews Bungalow Court |
| Stanford-Lathrop House |
| Stansbury House |
| Stanton, Phillip Ackley, House |
| State Asylum for the Deaf,Dumb and Blind |
| State Theatre |
| Station and General Office, California Southern Railroad |
| Steedman Estate |
| Steinbeck, John, House |
| Stevens House |
| Stevenson, Robert Louis, Branch |
| Stevens, Sherman, House |
| St. Francis by-the-Sea American Catholic Church |
| St. George Hotel |
| St. George Reef Light Station |
| St. Helena Catholic Church |
| St. Helena High School |
| St. Helena Historic Commercial District |
| St. Helena Public Cemetery |
| St. Helena Public Library |
| Stimson House |
| St. James Park Historic District |
| St. James Square Historic District |
| St. John's Episcopal Church |
| St. John's Episcopal Church |
| St. John's Lutheran Church |
| St. John's Presbyterian Church |
| St. Joseph Catholic Church, Rectory and Cemetery |
| St. Joseph's Basilica |
| St. Joseph's Church and Complex |
| St. Joseph's Home for the Aged |
| St. Joseph's Hospital |
| St. Joseph's Roman Catholic Church |
| St. Louis Catholic Church |
| St. Matthew's Episcopal Church |
| St. Michael's Episcopal Church |
| Stockton Savings and Loan Society Bank |
| Stoesser Block and Annex |
| Stone House |
| Stoner House |
| Storer House |
| Storrier-Stearns Japanese Garden |
| Stoutenburgh House |
| St. Paulus Lutheran Church |
| Straight, Charles E., House |
| Strathmore Apartments |
Data from United States Park Service and Wikidata
