| Real Maryland F.C. | Rockville | 2007 | Richard Montgomery High School |
| Rhode Island Stingrays | — | 1995 | — |
| Rio Grande Valley Bravos FC | — | 2008 | — |
| Rochester Thunder | — | 2008 | — |
| Salem City FC | Greensboro | 1993 | Macpherson Stadium |
| San Diego Gauchos | — | 2002 | Torero Stadium |
| San Diego Zest FC | San Diego | 2016 | RIMAC Sports Complex |
| San Francisco City FC | San Francisco | 2001 | Negoesco Stadium |
| San Francisco Glens | San Francisco | 1961 | Boxer Stadium |
| San Gabriel Valley Highlanders | Glendale | 1997 | — |
| San Jose Earthquakes U23 | — | 2013 | — |
| San Jose Frogs | San Jose | 2005 | — |
| SC United Bantams | Columbia | 2011 | — |
| Seacoast United Phantoms | Portsmouth | 1996 | — |
| Sioux Falls Spitfire | — | 2001 | O'Gorman Catholic High School |
| SoCal Surf | Carlsbad | 2015 | Army and Navy Academy |
| Southern California Seahorses | La Mirada | 2001 | — |
| Southern West Virginia King's Warriors | — | 2012 | East River Soccer Complex |
| Spokane Shadow | Spokane | 1996 | Joe Albi Stadium |
| Spokane Spiders | — | 2006 | Joe Albi Stadium |
| Springfield Demize | Springfield | 2006 | — |
| Springfield Storm | — | 2005 | — |
| St. Louis Lions | St. Louis | 2006 | — |
| St. Petersburg FC | St. Petersburg | — | — |
| SW Florida Adrenaline | — | 2012 | Estero High School |
| Tampa Bay Hawks | — | 2000 | — |
| Tobacco Road FC | — | 2013 | Durham County Stadium |
| Toledo Slayers | — | 2003 | Lucas County Recreation Center |
| Treasure Coast Tritons | Port St. Lucie | 2016 | — |
| Twin Cities Phoenix | — | 1997 | — |
| Ventura County Fusion | Ventura | 2006 | Ventura College |
| Vermont Green FC | Burlington | October 12, 2021 | Virtue Field |
| Vermont Voltage | Saint Albans | 1997 | — |
| Virginia Legacy | — | 2002 | — |
| VSI Tampa Bay FC | — | 2011 | Plant City Stadium |
| Washington Crossfire | — | 2002 | Redmond High School |
| West Dallas Kings | — | 2001 | — |
| West Michigan Edge | — | 1995 | — |
| West Virginia Chaos | Charleston | 2003 | Schoenbaum Stadium |
| Westchester Flames | New York City | 1999 | City Park Stadium |
| Western Mass Pioneers | Ludlow | 1998 | Lusitano Stadium |
| Willamette Valley Firebirds | — | 1992 | — |
| Wilmington Hammerheads FC | Wilmington | 1996 | Legion Stadium |
| Wisconsin Rebels | — | 1998 | — |
| Worcester Kings | — | 2002 | — |
| Yakima Reds | — | 1995 | — |