| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Mabella | city | Ontario | Canada | 48.60 | -89.98 | 1669 | 0 |
| Maberly | city | Ontario | Canada | 44.84 | -76.54 | 830 | 456 |
| MacTier | city | Ontario | Canada | 45.13 | -79.77 | 830 | 456 |
| Macdiarmid | city | Ontario | Canada | 49.43 | -88.12 | 1069 | 150 |
| Mackenzie | city | Ontario | Canada | 48.55 | -88.97 | 1000 | 543 |
| Maclennan | city | Ontario | Canada | 46.67 | -80.75 | 980 | 1756 |
| Maclennan Township | city | Ontario | Canada | 46.67 | -80.75 | 980 | 1756 |
| Madawaska | city | Ontario | Canada | 45.50 | -78.00 | 1128 | 0 |
| Madoc | city | Ontario | Canada | 44.52 | -77.48 | 830 | 3090 |
| Madsen | city | Ontario | Canada | 50.97 | -93.92 | 1669 | 141 |
| Magnetawan | city | Ontario | Canada | 45.67 | -79.63 | 944 | 468 |
| Maidstone | city | Ontario | Canada | 42.21 | -82.89 | 830 | 7331 |
| Maitland | city | Ontario | Canada | 44.64 | -75.61 | 291 | 6658 |
| Malachi | city | Ontario | Canada | 49.93 | -94.98 | 1079 | 0 |
| Mallorytown | city | Ontario | Canada | 44.48 | -75.88 | 311 | 1393 |
| Malton | city | Ontario | Canada | 43.70 | -79.63 | 830 | 202646 |
| Mammamattawa | city | Ontario | Canada | 50.42 | -84.37 | 410 | 0 |
| Mammawemattawa | city | Ontario | Canada | 50.42 | -84.37 | 410 | 0 |
| Manitouaning | city | Ontario | Canada | 45.73 | -81.80 | 830 | 663 |
| Manitouwadge | city | Ontario | Canada | 49.13 | -85.80 | 1017 | 1874 |
| Manitowaning | city | Ontario | Canada | 45.73 | -81.80 | 830 | 663 |
| Manomin | city | Ontario | Canada | 48.88 | -93.80 | 1204 | 16 |
| Manotick | city | Ontario | Canada | 45.23 | -75.69 | 285 | 25411 |
| Manvers | city | Ontario | Canada | 44.13 | -78.67 | 1010 | 1802 |
| Maple | city | Ontario | Canada | 43.86 | -79.51 | 830 | 56290 |
| Maple Grove | city | Ontario | Canada | 44.37 | -76.20 | 275 | 6579 |
| Mapleton | city | Ontario | Canada | 42.82 | -81.07 | 830 | 2740 |
| Marathon | city | Ontario | Canada | 48.75 | -86.37 | 977 | 3054 |
| Markdale | city | Ontario | Canada | 44.32 | -80.65 | 1669 | 3125 |
| Markham | city | Ontario | Canada | 43.88 | -79.26 | 830 | 107608 |
| Markhamo | city | Ontario | Canada | 43.88 | -79.26 | 830 | 107608 |
| Markstay | city | Ontario | Canada | 46.48 | -80.53 | 830 | 576 |
| Marmora | city | Ontario | Canada | 44.48 | -77.68 | 830 | 3167 |
| Marten Falls First Nation | city | Ontario | Canada | 51.62 | -85.93 | 830 | 58 |
| Martintown | city | Ontario | Canada | 45.16 | -74.71 | 213 | 17 |
| Massey | city | Ontario | Canada | 46.20 | -82.08 | 830 | 1286 |
| Matachewan | city | Ontario | Canada | 48.00 | -80.65 | 1089 | 26 |
| Matheson | city | Ontario | Canada | 48.53 | -80.47 | 892 | 149 |
| Matheson Station | city | Ontario | Canada | 48.53 | -80.47 | 892 | 149 |
| Mattawa | city | Ontario | Canada | 46.32 | -78.70 | 830 | 2379 |
| Mattawan | city | Ontario | Canada | 46.33 | -78.83 | 830 | 15 |
| Mattice | city | Ontario | Canada | 49.62 | -83.27 | 830 | 138 |
| Maxville | city | Ontario | Canada | 45.29 | -74.86 | 347 | 1707 |
| Maynooth | city | Ontario | Canada | 45.23 | -77.93 | 1669 | 390 |
| McDonalds Corners | city | Ontario | Canada | 44.96 | -76.52 | 830 | 315 |
| McDougall Mills | city | Ontario | Canada | 50.17 | -91.53 | 1210 | 0 |
| McGregor | city | Ontario | Canada | 42.15 | -82.97 | 830 | 5809 |
| McIntosh | city | Ontario | Canada | 49.98 | -93.62 | 1669 | 0 |
| McIntosh Springs | city | Ontario | Canada | 48.63 | -80.87 | 921 | 308 |
| McKenzie Island | city | Ontario | Canada | 51.08 | -93.83 | 1213 | 258 |
| Meaford | city | Ontario | Canada | 44.60 | -80.58 | 830 | 5306 |
| Melancthon | city | Ontario | Canada | 44.11 | -80.25 | 1696 | 3365 |
| Melbourne | city | Ontario | Canada | 42.82 | -81.55 | 830 | 328 |
| Meldrum Bay | city | Ontario | Canada | 45.92 | -83.12 | 830 | 0 |
| Melrose | city | Ontario | Canada | 43.00 | -81.40 | 862 | 17854 |
| Merlin | city | Ontario | Canada | 42.24 | -82.23 | 830 | 269 |
| Merrickville | city | Ontario | Canada | 44.92 | -75.83 | 347 | 1548 |
| Metagama | city | Ontario | Canada | 47.10 | -81.93 | 1669 | 0 |
| Metcalfe | city | Ontario | Canada | 45.24 | -75.47 | 311 | 4465 |
| Meyersburg | city | Ontario | Canada | 44.25 | -77.82 | 380 | 4048 |
| Michipicoten | city | Ontario | Canada | 47.96 | -84.90 | 830 | 138 |
| Michipicoten Harbor | city | Ontario | Canada | 47.96 | -84.90 | 830 | 138 |
| Michipicoten Harbour | city | Ontario | Canada | 47.96 | -84.90 | 830 | 138 |
| Michipicoton | city | Ontario | Canada | 47.96 | -84.90 | 830 | 138 |
| Middleville | city | Ontario | Canada | 45.10 | -76.39 | 830 | 596 |
| Midhurst | city | Ontario | Canada | 44.45 | -79.73 | 830 | 13496 |
| Midland | city | Ontario | Canada | 44.75 | -79.90 | 830 | 29909 |
| Mildmay | city | Ontario | Canada | 44.04 | -81.12 | 1059 | 2361 |
| Millbank | city | Ontario | Canada | 43.57 | -80.84 | 1246 | 1272 |
| Millbrook | city | Ontario | Canada | 44.15 | -78.46 | 830 | 4693 |
| Millhaven | city | Ontario | Canada | 44.20 | -76.75 | 298 | 4921 |
| Milnet | city | Ontario | Canada | 46.82 | -80.95 | 1099 | 273 |
| Milton | city | Ontario | Canada | 43.51 | -79.88 | 830 | 15020 |
| Milton West | city | Ontario | Canada | 43.51 | -79.88 | 830 | 15020 |
| Milverton | city | Ontario | Canada | 43.57 | -80.92 | 1236 | 3901 |
| Mimico | city | Ontario | Canada | 43.60 | -79.50 | 246 | 151562 |
| Minahico | city | Ontario | Canada | 49.01 | -94.38 | 1102 | 100 |
| Minaki | city | Ontario | Canada | 49.98 | -94.65 | 1099 | 0 |
| Minataree | city | Ontario | Canada | 50.23 | -88.05 | 1095 | 0 |
| Minden | city | Ontario | Canada | 44.93 | -78.73 | 944 | 545 |
| Mine Centre | city | Ontario | Canada | 48.79 | -92.64 | 1197 | 0 |
| Minnietakie | city | Ontario | Canada | 49.80 | -93.08 | 1200 | 215 |
| Minnitaki | city | Ontario | Canada | 49.80 | -93.08 | 1200 | 215 |
| Missanabie | city | Ontario | Canada | 48.30 | -84.08 | 1082 | 0 |
| Mississauga | city | Ontario | Canada | 43.15 | -79.50 | 830 | 16974 |
| Mississippi Station | city | Ontario | Canada | 44.93 | -76.68 | 830 | 139 |
| Mitchell | city | Ontario | Canada | 43.47 | -81.20 | 1105 | 7680 |
| Mitchell's Bay | city | Ontario | Canada | 42.47 | -82.41 | 830 | 0 |
| Mitchell’s Bay | city | Ontario | Canada | 42.47 | -82.41 | 830 | 0 |
| Mobert | city | Ontario | Canada | 48.68 | -85.65 | 1099 | 262 |
| Mohawk | city | Ontario | Canada | 44.23 | -77.03 | 288 | 4159 |
| Monkton | city | Ontario | Canada | 43.59 | -81.08 | 1167 | 376 |
| Monteith | city | Ontario | Canada | 48.65 | -80.68 | 885 | 385 |
| Montizambert | city | Ontario | Canada | 48.68 | -85.65 | 1099 | 262 |
| Montreal River Harbour | city | Ontario | Canada | 47.24 | -84.64 | 1095 | 0 |
| Moonbeam | city | Ontario | Canada | 49.35 | -82.15 | 830 | 447 |
| Moor Lake Station | city | Ontario | Canada | 46.13 | -77.70 | 830 | 0 |
| Moorefield | city | Ontario | Canada | 43.76 | -80.74 | 1669 | 1341 |
| Mooretown | city | Ontario | Canada | 42.84 | -82.46 | 830 | 13061 |
| Moose Creek | city | Ontario | Canada | 45.26 | -74.97 | 272 | 1063 |
| Moose Factory | city | Ontario | Canada | 51.25 | -80.60 | 29 | 1944 |
| Moose Harbor | city | Ontario | Canada | 51.27 | -80.65 | 32 | 2038 |
| Moose Island | city | Ontario | Canada | 51.25 | -80.60 | 29 | 1944 |
| Moosonee | city | Ontario | Canada | 51.27 | -80.65 | 32 | 2038 |
| Morewood | city | Ontario | Canada | 45.18 | -75.28 | 239 | 216 |
| Morpeth | city | Ontario | Canada | 42.39 | -81.84 | 830 | 2159 |
| Morrisburg | city | Ontario | Canada | 44.90 | -75.18 | 209 | 5156 |
| Morriston | city | Ontario | Canada | 43.45 | -80.12 | 1049 | 1494 |
| Morson | city | Ontario | Canada | 49.10 | -94.32 | 1059 | 238 |
| Morton | city | Ontario | Canada | 44.54 | -76.19 | 396 | 965 |
| Mount Albert | city | Ontario | Canada | 44.13 | -79.31 | 895 | 4763 |
| Mount Brydges | city | Ontario | Canada | 42.91 | -81.49 | 830 | 3973 |
| Mount Carmel | city | Ontario | Canada | 43.26 | -81.62 | 830 | 523 |
| Mount Elgin | city | Ontario | Canada | 42.96 | -80.79 | 948 | 292 |
| Mount Forest | city | Ontario | Canada | 43.98 | -80.73 | 1669 | 9097 |
| Mount Hope | city | Ontario | Canada | 43.16 | -79.92 | 830 | 22434 |
| Mount Pleasant | city | Ontario | Canada | 44.23 | -77.03 | 288 | 4159 |
| Mount Pleasant | city | Ontario | Canada | 43.08 | -80.31 | 830 | 13317 |
| Mount Saint Patrick | city | Ontario | Canada | 45.34 | -76.87 | 830 | 101 |
| Mountain | city | Ontario | Canada | 45.04 | -75.50 | 259 | 1203 |
| Mountain Grove | city | Ontario | Canada | 44.74 | -76.84 | 830 | 298 |
| Mountain View | city | Ontario | Canada | 44.08 | -77.37 | 288 | 1621 |
| Mt Forest | city | Ontario | Canada | 43.98 | -80.73 | 1669 | 9097 |
| Muirkirk | city | Ontario | Canada | 42.52 | -81.77 | 830 | 1015 |
| Mull | city | Ontario | Canada | 42.40 | -81.99 | 830 | 2753 |
| Muskoka | city | Ontario | Canada | 45.00 | -79.30 | 892 | 6166 |
| Muskoka Falls | city | Ontario | Canada | 45.00 | -79.30 | 892 | 6166 |
| Myrtle Station | city | Ontario | Canada | 44.02 | -78.97 | 830 | 18319 |