Surname M
| SURNAME | TOWNSHIP | RESEARCHER |
| Mackeben⁄Mackaben | Doug Plowman | |
| Magden | Sophia Preston | |
| Magnuson | Rick Albright | |
| Mahoney | Lake Bluff | Alice Nicholson |
| Maiman⁄Maimann | Wauconda | Susan Edgell |
| Mainmann⁄Meimann⁄Meumann | Eric Groenke | |
| Malmberg | Chris Fitzgerald | |
| Manley | Waukegan, and Cook County, IL | Pat Williams Manley |
| Mann | Deb D | |
| Marko | All around Illinois | Barb Morgan |
| Mason | Lake Bluff, 1910 | Kathy Stonecipher |
| Masterson | ca 1880s, Lake Forest | Robin Maloney |
| Masterson | Lake Forest⁄Deerfield | Noah Reinholm |
| Maxson | Waukegan? | Annette Briggs |
| McAdam | Barrington, 1884-?, then Wisconsin | Jeff Furlong |
| McCloud | RN | |
| McDevitt | Fox Lake | Michelle LoSchiavo |
| McQuivey website |
Candee Reinking Lebrun | |
| McLaughlin | Molly Leonard | |
| McLean | Laura Hewitt | |
| McNeany⁄McNinny | Mary Kay Mullen | |
| McQuivey | Candy Reinking Lebrun | |
| McVey | Mary Kay Mullen | |
| Meadors | Laura Hewitt | |
| Metz | Waukegan | Pat Williams Manley |
| Metzger | Dave Kliss | |
| Meyer | Long Grove, Lake Zurich | Dewayne Parfitt |
| Meyer | Brenda | |
| Meyer | Tammy Lillich | |
| Miller | K. Don Thompson | |
| Miller | Joy Mulholland | |
| Miller | 1900-1915 | Peggy Sue Miller |
| Minsky⁄Minskie | Wauconda | Susan Edgell |
| Mix | Newport - 1850's to 1880 | Doni Wright |
| Monaghan⁄Monahan | John Paul Cox | |
| Moran | Half Day | Barbara Pratt Opitz |
| Morse | Wauconda | Roger Peterson |
| Mosher, Musser | after 1848, Ivanhoe, Volo, Libertyville, Mundelein | Cindy Dorfler-Hederer or Sharon Dorfler Kemble |
| Mosser⁄Mosier⁄Mossier | Long Grove area; 1850s - ? | Diana Vickery |
| Mota | Steve Regul | |
| Murbach | Long Grove⁄Palatine; 1850s - ? | Diana Vickery |
| Murray | Fremont & Wauconda | Vicki Mazur |
| Myers⁄Myer⁄Meyer | Antioch | Denise Parsons |