| Smith | 3,600 | Smith Center | Kansas | Lincoln, NE | View → |
| Smith | 21,000 | Carthage | Tennessee | Nashville, TN | View → |
| Smyth | 30,000 | Marion | Virginia | Tri-Cities, TN/VA | View → |
| Snohomish | 900,000 | Everett | Washington | Seattle, WA | View → |
| Snyder | 41,000 | Selinsgrove | Pennsylvania | Scranton, PA-Binghamton, NY | View → |
| Socorro | 18,500 | Socorro | New Mexico | Albuquerque, NM | View → |
| Solano | 460,000 | Fairfield | California | San Francisco, CA | View → |
| Somerset | 73,100 | Somerset | Pennsylvania | Johnstown-Altoona-State College, PA | View → |
| Somerset | 345,361 | Somerville | New Jersey | New York, NY | View → |
| Somerset | 27,000 | Princess Anne | Maryland | Norfolk, VA-Salisbury, MD | View → |
| Somerset | 52,000 | Skowhegan | Maine | Portland-Bangor, ME | View → |
| Somervell | 9,000 | Glen Rose | Texas | Dallas-Fort Worth, TX | View → |
| Sonoma | 500,000 | Santa Rosa | California | San Francisco, CA | View → |
| Southampton | 18,000 | Courtland | Virginia | Norfolk, VA-Salisbury, MD | View → |
| Spalding | 68,000 | Griffin | Georgia | Atlanta, GA | View → |
| Spartanburg | 330,000 | Spartanburg | South Carolina | Greenville, SC-Asheville, NC | View → |
| Spencer | 21,000 | Rockport | Indiana | Louisville, KY-Evansville, IN | View → |
| Spencer | 22,000 | Taylorsville | Kentucky | Louisville, KY-Evansville, IN | View → |
| Spink | 6,600 | Redfield | South Dakota | Sioux Falls-Rapid City, SD | View → |
| Spokane | 540,000 | Spokane | Washington | Spokane, WA | View → |
| Spotsylvania | 140,000 | Fredericksburg | Virginia | Washington, DC | View → |
| St. Bernard | 44,000 | Chalmette | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. Charles | 54,000 | Luling | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. Charles | 410,000 | St. Charles | Missouri | St. Louis, MO | View → |
| St. Clair | 94,400 | Pell City | Alabama | Birmingham-Huntsville, AL | View → |
| St. Clair | 160,000 | Port Huron | Michigan | Detroit, MI-Toledo, OH | View → |
| St. Clair | 9,600 | Osceola | Missouri | Springfield, MO | View → |
| St. Clair | 250,000 | Belleville | Illinois | St. Louis, MO | View → |
| St. Croix | 93,000 | Hudson | Wisconsin | Minneapolis-St. Paul, MN | View → |
| St. Francis | 25,000 | Forrest City | Arkansas | Memphis, TN | View → |
| St. Francois | 67,000 | Farmington | Missouri | St. Louis, MO | View → |
| St. Helena | 11,500 | Greensburg | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. James | 21,000 | Lutcher | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. John The Baptist | 43,500 | LaPlace | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. Johns | 309,700 | St. Augustine | Florida | Jacksonville-Tallahassee, FL | View → |
| St. Joseph | 270,000 | South Bend | Indiana | Chicago, IL | View → |
| St. Joseph | 62,000 | Three Rivers | Michigan | Grand Rapids, MI | View → |
| St. Landry | 82,000 | Opelousas | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. Lawrence | 108,000 | Potsdam | New York | Albany-Utica-Elmira, NY | View → |
| St. Louis | 199,000 | Duluth | Minnesota | Green Bay, WI-Duluth, MN | View → |
| St. Louis | 1,000,000 | Clayton | Missouri | St. Louis, MO | View → |
| St. Louis City | 294,000 | St. Louis | Missouri | St. Louis, MO | View → |
| St. Lucie | 349,800 | Port St. Lucie | Florida | Miami-West Palm Beach, FL | View → |
| St. Martin | 51,500 | St. Martinville | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. Mary | 47,000 | Morgan City | Louisiana | New Orleans-Baton Rouge, LA | View → |
| St. Mary's | 120,000 | Leonardtown | Maryland | Washington, DC | View → |
| St. Tammany | 270,000 | Slidell | Louisiana | New Orleans-Baton Rouge, LA | View → |
| Stafford | 160,000 | Stafford | Virginia | Washington, DC | View → |
| Stafford | 4,200 | St. John | Kansas | Wichita, KS | View → |
| Stanislaus | 580,000 | Modesto | California | Sacramento, CA | View → |
