M
- Mabel
- Macedonia
- Machesney Park
- Mackinaw
- Macomb
- Macon
- Macoupin
- Madison
- Madonnaville
- Maeystown
- Magnet
- Magnolia
- Magnolia Corner
- Mahomet
- Maizetown
- Makanda
- Malden
- Mallard
- Malta
- Malvern
- Manchester
- Manhattan
- Manito
- Manley
- Manlius
- Mannon
- Mansfield
- Manteno
- Manville
- Maple Grove
- Maple Park
- Maple Point
- Maples Mill
- Mapleton
- Maquon
- Marblehead
- Marbletown
- Marceline
- Marco
- Marcoe
- Marcus
- Marengo
- Marietta
- Marigold
- Marine
- Marion
- Marissa
- Mark
- Markham
- Marletta
- Marley
- Marlow
- Maroa
- Marquette
- Marquette Heights
- Marseilles
- Marshall
- Marston
- Martinsburg
- Martinsville
- Martinton
- Marydale
- Maryland
- Maryville
- Marywood
- Mascoutah
- Mason
- Mason City
- Massbach
- Matanzas Beach
- Matherville
- Matteson
- Matthews
- Mattoon
- Maud
- Maunie
- Maxwell
- Maxwell
- Mayberry
- Mayfair
- Mays
- Maysville
- Maytown
- Mayview
- Maywood
- Mazon
- Mazonia
- McCall
- McClay Orchard
- McClure
- McClusky
- McCook
- McCormick
- McCormickville
- McCown
- McCulley Subdivision
- McCullom Lake
- McDowell
- McGirr
- McHenry
- McKeen
- McKinley
- McKinley Park
- McLean
- McLeansboro
- McNabb
- McNulta
- McQueen
- McVey
- Meadowbrook
- Meadows
- Mechanicsburg
- Media
- Medinah
- Medora
- Meeks
- Melody
- Melrose
- Melrose Park
- Melville
- Melvin
- Melwood
- Menard
- Mendon
- Mendota
- Menominee
- Meppen
- Meredith
- Meredosia
- Meriden
- Mermet
- Merna
- Merriam
- Merrimac
- Merrionette Park
- Merritt
- Metamora
- Metcalf
- Metropolis
- Mettawa
- Meyer
- Meyer
- Michael
- Middlebury
- Middle Creek
- Middle Grove
- Middlepoint
- Middlesworth
- Middleton
- Middletown
- Midland City
- Midlothian
- Midway
- Midway
- Midway
- Midway
- Midway
- Milan
- Miles Station
- Milford
- Milla
- Millbrook
- Millburn
- Mill Creek
- Milledgeville
- Miller
- Miller City
- Millersburg
- Millersville
- Millhurst
- Millington
- Millsdale
- Mill Shoals
- Millstadt
- Millville
- Millville
- Milmine
- Milne
- Milo
- Milroy
- Milton
- Mindale
- Mindale
- Mineral
- Minier
- Minonk
- Minonk Junction
- Minooka
- Mira
- Missal
- Mitchell
- Mitchells Subdivision
- Mitchellsville
- Mitchie
- Moccasin
- Mode
- Modena
- Modesto
- Modoc
- Mokena
- Moline
- Momence
- Monee
- Monica
- Monmouth
- Monroe Center
- Monroe City
- Mont
- Monterey
- Montezuma
- Montgomery
- Monticello
- Montrose
- Moonshine
- Moores Corner
- Mooseheart
- Morganville
- Moriah
- Moro
- Moronts
- Morrelville
- Morris
- Morrison
- Morrisonville
- Morristown
- Morse
- Morseville
- Mortimer
- Morton
- Morton Grove
- Moscow
- Mossville
- Mound City
- Mounds
- Mound Station
- Mountain Glenn
- Mount Auburn
- Mount Carbon
- Mount Carmel
- Mount Carroll
- Mount Clare
- Mount Erie
- Mount Fulcher
- Mountjoy
- Mount Morris
- Mount Olive
- Mount Pleasant
- Mount Prospect
- Mount Pulaski
- Mount Sterling
- Mount Vernon
- Mount Zion
- Moweaqua
- Mozier
- Mt. Carmel
- Mt Carroll
- Mt Palatine
- Mt Sterling
- Muddy
- Mulberry Grove
- Mulkeytown
- Muncie
- Mundelein
- Munger
- Munster
- Murdock
- Murphysboro
- Murrayville
- Myron
- Myrtle