| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Mabel | city | Illinois | United States | 39.88 | -87.69 | 830 | |
| Macedonia | city | Illinois | United States | 38.05 | -88.71 | 830 | |
| Machesney Park | city | Illinois | United States | 42.35 | -89.04 | 830 | |
| Mackinaw | city | Illinois | United States | 40.54 | -89.36 | 830 | |
| Mackinaw Dells | city | Illinois | United States | 40.62 | -89.23 | 830 | |
| Mackville | city | Illinois | United States | 39.81 | -88.48 | 830 | |
| Macomb | city | Illinois | United States | 40.46 | -90.67 | 830 | |
| Macon | city | Illinois | United States | 39.71 | -89.00 | 830 | |
| Macoupin | city | Illinois | United States | 39.21 | -89.96 | 830 | |
| Madison | city | Illinois | United States | 38.68 | -90.16 | 406 | |
| Madison Station | city | Illinois | United States | 38.68 | -90.15 | 406 | |
| Madonnaville | city | Illinois | United States | 38.27 | -90.25 | 830 | |
| Maeystown | city | Illinois | United States | 38.22 | -90.23 | 830 | |
| Magnet | city | Illinois | United States | 39.44 | -88.40 | 830 | |
| Magnolia | city | Illinois | United States | 41.11 | -89.19 | 830 | |
| Magnolia Corner | city | Illinois | United States | 39.09 | -88.85 | 830 | |
| Mahomet | city | Illinois | United States | 40.20 | -88.40 | 830 | |
| Maizetown | city | Illinois | United States | 39.95 | -87.80 | 830 | |
| Makanda | city | Illinois | United States | 37.62 | -89.21 | 830 | |
| Malden | city | Illinois | United States | 41.42 | -89.37 | 830 | |
| Malibu Bay | city | Illinois | United States | 41.64 | -88.11 | 830 | |
| Mallard Creek | city | Illinois | United States | 42.11 | -87.84 | 830 | |
| Mallard Lake Estates | city | Illinois | United States | 41.61 | -88.00 | 830 | |
| Mallard Lake North | city | Illinois | United States | 41.97 | -88.37 | 830 | |
| Mallard Lake South | city | Illinois | United States | 41.96 | -88.37 | 830 | |
| Malta | city | Illinois | United States | 41.93 | -88.86 | 902 | |
| Malvern | city | Illinois | United States | 41.86 | -89.89 | 830 | |
| Mammoth Springs | city | Illinois | United States | 41.85 | -87.95 | 830 | |
| Manchester | city | Illinois | United States | 39.54 | -90.33 | 830 | |
| Mancuso Village Park | city | Illinois | United States | 42.18 | -89.07 | 830 | |
| Mandell | city | Illinois | United States | 41.87 | -87.75 | 830 | |
| Manhattan | city | Illinois | United States | 41.42 | -87.99 | 830 | |
| Manito | city | Illinois | United States | 40.43 | -89.78 | 830 | |
| Manley | city | Illinois | United States | 40.58 | -90.43 | 830 | |
| Manlius | city | Illinois | United States | 41.46 | -89.67 | 830 | |
| Mannon | city | Illinois | United States | 41.23 | -90.96 | 830 | |
| Mansfield | city | Illinois | United States | 40.21 | -88.51 | 830 | |
| Manteno | city | Illinois | United States | 41.25 | -87.83 | 830 | |
| Manus North Shore Estates | city | Illinois | United States | 42.14 | -87.85 | 830 | |
| Manville | city | Illinois | United States | 41.06 | -88.77 | 830 | |
| Maple | city | Illinois | United States | 38.86 | -89.88 | 830 | |
| Maple Grove | city | Illinois | United States | 38.53 | -88.09 | 830 | |
| Maple Leaf Estates | city | Illinois | United States | 41.65 | -87.98 | 830 | |
| Maple Leaf Mobile Home Park | city | Illinois | United States | 42.33 | -89.03 | 830 | |
| Maple Park | city | Illinois | United States | 41.91 | -88.60 | 859 | |
| Maple Point | city | Illinois | United States | 39.33 | -88.11 | 830 | |
| Maple Ridge | city | Illinois | United States | 42.13 | -87.84 | 830 | |
| Maples Mill | city | Illinois | United States | 40.43 | -90.03 | 830 | |
| Mapleton | city | Illinois | United States | 40.57 | -89.73 | 830 | |
| Maplewood | city | Illinois | United States | 41.93 | -87.70 | 830 | |
| Maplewood Courts | city | Illinois | United States | 41.88 | -87.69 | 830 | |
| Maplewood Park | city | Illinois | United States | 38.58 | -90.18 | 406 | |
| Maquon | city | Illinois | United States | 40.80 | -90.17 | 830 | |
| Marblehead | city | Illinois | United States | 39.84 | -91.37 | 830 | |
| Marbletown | city | Illinois | United States | 40.23 | -90.20 | 830 | |
| Marcelline | city | Illinois | United States | 40.12 | -91.37 | 830 | |
| Marcoe | city | Illinois | United States | 38.27 | -88.97 | 830 | |
| Marcus | city | Illinois | United States | 42.16 | -90.20 | 830 | |
| Marden Estates | city | Illinois | United States | 42.17 | -88.02 | 830 | |
| Marengo | city | Illinois | United States | 42.25 | -88.61 | 843 | |
| Marietta | city | Illinois | United States | 40.50 | -90.39 | 830 | |
| Marigold | city | Illinois | United States | 38.08 | -90.01 | 830 | |
| Marilyn's Estates | city | Illinois | United States | 41.62 | -87.96 | 830 | |
| Marine | city | Illinois | United States | 38.79 | -89.78 | 830 | |
| Marion | city | Illinois | United States | 37.73 | -88.93 | 830 | |
| Marion | city | Illinois | United States | 38.55 | -88.11 | 830 | |
| Marion Mobile Home Village | city | Illinois | United States | 37.72 | -88.91 | 830 | |
| Marissa | city | Illinois | United States | 38.25 | -89.75 | 830 | |
| Mark | city | Illinois | United States | 41.26 | -89.25 | 830 | |
| Markham | city | Illinois | United States | 39.75 | -90.33 | 830 | |
| Markham | city | Illinois | United States | 41.59 | -87.69 | 830 | |
| Markham City | city | Illinois | United States | 38.33 | -88.72 | 830 | |
| Markus Subdivision | city | Illinois | United States | 42.13 | -87.85 | 830 | |
| Marlen Subdivision | city | Illinois | United States | 42.13 | -87.85 | 830 | |
| Marley | city | Illinois | United States | 39.51 | -87.62 | 830 | |
| Marley | city | Illinois | United States | 41.55 | -87.93 | 830 | |
| Marlow | city | Illinois | United States | 38.32 | -88.79 | 830 | |
| Maroa | city | Illinois | United States | 40.04 | -88.96 | 830 | |
| Marquette | city | Illinois | United States | 41.33 | -89.26 | 830 | |
| Marquette Heights | city | Illinois | United States | 40.62 | -89.60 | 830 | |
| Marquette Manor | city | Illinois | United States | 41.79 | -87.69 | 830 | |
| Marquettes Landing | city | Illinois | United States | 41.64 | -88.12 | 830 | |
| Marseilles | city | Illinois | United States | 41.33 | -88.71 | 830 | |
| Marshall | city | Illinois | United States | 39.39 | -87.69 | 830 | |
| Marshall Field Garden Apartments | city | Illinois | United States | 41.91 | -87.64 | 830 | |
| Marshall Landing | city | Illinois | United States | 38.96 | -90.51 | 830 | |
| Marston | city | Illinois | United States | 41.31 | -90.80 | 830 | |
| Martin (historical) | city | Illinois | United States | 41.15 | -90.64 | 830 | |
| Martin Luther | city | Illinois | United States | 41.95 | -87.77 | 830 | |
| Martinsburg | city | Illinois | United States | 39.52 | -90.84 | 830 | |
| Martinsville | city | Illinois | United States | 39.34 | -87.88 | 830 | |
| Martinton | city | Illinois | United States | 40.92 | -87.73 | 830 | |
| Mary Meadows | city | Illinois | United States | 41.94 | -88.45 | 898 | |
| Marydale | city | Illinois | United States | 38.70 | -89.37 | 830 | |
| Maryland | city | Illinois | United States | 42.07 | -89.55 | 853 | |
| Maryland Place | city | Illinois | United States | 38.73 | -90.11 | 416 | |
| Maryland Subdivision | city | Illinois | United States | 42.12 | -87.86 | 830 | |
| Maryville | city | Illinois | United States | 38.72 | -89.96 | 830 | |
| Marywood | city | Illinois | United States | 41.79 | -88.29 | 830 | |
| Mascoutah | city | Illinois | United States | 38.49 | -89.79 | 830 | |
| Mason | city | Illinois | United States | 37.52 | -89.25 | 830 | |
| Mason | city | Illinois | United States | 38.95 | -88.62 | 830 | |
| Mason City | city | Illinois | United States | 40.20 | -89.70 | 830 | |
| Massac City | city | Illinois | United States | 37.14 | -88.72 | 298 | |
| Massbach | city | Illinois | United States | 42.25 | -90.12 | 921 | |
| Matanzas | city | Illinois | United States | 40.23 | -90.10 | 830 | |
| Matanzas Beach | city | Illinois | United States | 40.24 | -90.10 | 830 | |
| Matherville | city | Illinois | United States | 41.26 | -90.61 | 830 | |
| Matteson | city | Illinois | United States | 41.50 | -87.71 | 830 | |
| Matthews | city | Illinois | United States | 37.97 | -89.37 | 387 | |
| Matthews Junction | city | Illinois | United States | 37.95 | -89.37 | 380 | |
| Mattoon | city | Illinois | United States | 39.48 | -88.37 | 830 | |
| Maud | city | Illinois | United States | 38.40 | -87.86 | 830 | |
| Maunie | city | Illinois | United States | 38.04 | -88.05 | 354 | |
| Maxwell | city | Illinois | United States | 40.69 | -89.70 | 830 | |
| Maxwell (historical) | city | Illinois | United States | 39.63 | -89.90 | 830 | |
| Mayberry | city | Illinois | United States | 38.27 | -88.55 | 830 | |
| Mayfair | city | Illinois | United States | 41.97 | -87.74 | 830 | |
| Mayfair | city | Illinois | United States | 40.62 | -89.41 | 830 | |
| Mays | city | Illinois | United States | 39.63 | -87.79 | 830 | |
| Maysville | city | Illinois | United States | 39.71 | -90.80 | 830 | |
| Maysville | city | Illinois | United States | 38.68 | -88.35 | 830 | |
| Maytown | city | Illinois | United States | 41.63 | -89.37 | 912 | |
| Mayview | city | Illinois | United States | 40.11 | -88.11 | 830 | |
| Maywood | city | Illinois | United States | 41.88 | -87.84 | 830 | |
| Maywood Manor | city | Illinois | United States | 42.20 | -89.05 | 830 | |
| Maywood i Illinois | city | Illinois | United States | 41.88 | -87.84 | 830 | |
| Mazon | city | Illinois | United States | 41.24 | -88.42 | 830 | |
| Mazonia | city | Illinois | United States | 41.21 | -88.28 | 830 |