Surname S
| SURNAME | TOWNSHIP | RESEARCHER |
| Salmon⁄Sammon | Waukegan | Anita Kelly Butkiewicz |
| Schenk | Brenda Gaetz | |
| Schill | Waukegan | Tiffany Gideon Bils |
| Schlict | Janice Lynn | |
| Schoeneberger | Buffalo Grove | Gretchen Leisen |
| Schoeneberger | Vernon Twp. 1880's | Mare Kimura |
| Schultz⁄Szulc | Shields & Waukegan Twp | Terri Miller |
| Schumacher⁄Schumaker | Barrington | Meg Jahnke |
| Schumacher | Stephanie Sampson | |
| Schutz | Stephanie Sampson | |
| Scott | Waukegan from Pennsylvania | Jayne Adams Piehl |
| Sebastian | Buffalo Grove & Aptakisic | Denise Thompson |
| Seingattin⁄Seinegatten | Buffalo Grove & Aptakisic | Denise Thompson |
| Sherman | Doris Carnahan | |
| Sherman | Waukegan? | Annette Briggs |
| Sherman | Grayslake | Cheryl Peterson |
| Short | Waukegan, 1850s - 1900 | Phil Smith |
| Shumaker | Benton | Jay Cunnington |
| Shields | Newport, Warren and possibly Benton | Corky Bell |
| Sickles | Grayslake | Dawn |
| Skerbec | Waukegan; from early 1900s | Bridget |
| Sleuman⁄Sluman | Patti Fellows | |
| Small | Andrew Pavlin | |
| Small | Ela, Fremont, Libertville, Mundelein 1880s-present | John Small |
| Smith (Schmitt?) | Wauconda, ca 1863 - ca 1881; Waukegan, ca 1887 - present | Philip D. Smith |
| Smith | Shields⁄Vernon⁄Libertyville | Marleen Van Horne |
| Smith | North Chicago and Waukegan⁄Wauconda | Deb McNelly |
| Solem | Libertyville | Cynthia Solem |
| Spaeth website |
Waukegan, 1920's on | Doug Spaeth |
| Speese | RESpeese@aol.com | |
| Spellman | John Spellman | |
| Spoerl | Tom Wagner | |
| Spoor | Waukegan | David Hyde |
| Srachta⁄Schrachta | Fox Lake⁄ Ingleside | Joe Wallace |
| Stafford | Waukegan, ca 1848-1900s | Harry Stafford |
| Stafford | Libertyville | Marilyn Bohac |
| Stanley website |
Jim Stanley | |
| Staranowicz | North Chicago, ?, 1907-? | Ruth Suchanski Kelly |
| Starovich | Shields & Waukegan Twp | Terri Miller |
| Staskiewicz | Shields & Waukegan Twp | Terri Miller |
| Steele | Shields | Clare |
| Stevens⁄Stephens | Waukegan 1840-50 | Pete Velsko |
| Stevens | Antioch 1840s; Waukegan ca 1870 to ca 1910 | Philip D. Smith |
| Stift | Antioch | Lee Koenig |
| Stober | Diane Boydstun | |
| Story | Thomas L. Story | |
| Streed⁄Strid | Ruth Streed Filstead | |
| Strickland | Ryerse | |
| Strobar | Waukegan | Joyce Higgins |
| Sturm | Long Grove, Lake Zurich | Dewayne Parfitt |
| Suchanski | North Chicago, 1907-1986 | Ruth Suchanski Kelly |
| Sullivan | Waukegan; 1930 | Teresa |
| Suittie⁄Suttie | TERRY W STEWART | |
| Svratka | Fox Lake | Joe Wallace |
| Swanson website |
Jim Stanley | |
| Szynalik | North Chicago | Edward Harazak |