1850 Atlas
| Name | What | Place | Pop | Other |
| Mabbettsville | PO | Washington twp, Dutchess Co, NY | ||
| Mabee's | PO | Jackson Co, OH | ||
| Macedon | PO | Mercer Co, OH | ||
| Macedon | PT | Wayne Co, NY | 2,384 | water by Mud creek |
| Macedon Centre | PO | Macedon twp, Wayne Co, NY | ||
| Macedonia | PV | Carroll Co, TN | ||
| Macedonia | PO | Montgomery Co, NC | ||
| Macedonia | PO | Potawatamie Co, IA | ||
| Machias | PT, CH | Washington Co, ME | 1,590 | seat of justice, water by west branch of Machias river |
| Machias | PT | Cattaraugus Co, NY | 1,242 | water by Ishua crerk & Lime lake outlet |
| Machias Port | PO | Washington Co, ME | water by Machias river | |
| Mackerel Corner | PO | Carroll Co, NH | ||
| Mackesville | PO | Clark Co, MS | ||
| Mackinac | PV, CH | Michilimackinac Co, MI | on an island of the same name, near the straits of Mackinaw | |
| Mackinaw | PO | Tazewell Co, IL | ||
| Macksburgh | PO | Giles Co, VA | ||
| Mack's Place | PO | St Clair Co, MI | ||
| Macksville | PV | Randolph Co, IN | ||
| Mackville | PV | Washington Co, KY | ||
| Macomb | PV, CH | McDonough Co, IL | ||
| Macomb | PT | Macomb Co, MI | 757 | water by Clinton river |
| Macomb | PO | St Lawrence Co, NY | ||
| Macon | PO | Powhattan Co, VA | ||
| Macon | City | Bibb Co, GA | seat of justice, water by Ocmulgee river at head of steam navigation | |
| Macon | PV | Marengo Co, AL | ||
| Macon | PV, CH | Noxubee Co, MS | seat of justice, water by Noxubee river | |
| Macon | PT | Lenawee Co, MI | 1,030 | water by south branch of Raisin river |
| Macon | PV | Fayette Co, TN | ||
| Madon Depot | PO | Warren Co, NC | ||
| Macopin | PO | Passaic Co, NJ | ||
| Macungie | PT | Lehigh Co, PA | water by Jordan & Little Lehigh creeks | |
| Madawaska | T | Aroostook Co, ME | 1,276 | water by St John's river |
| Madbury | T | Strafford Co, NH | 483 | water by Bellamy river |
| Mad River | T | Clark Co, OH | 1,496 | |
| Mad River | T | Champaign Co, OH | 1,907 | water by head branches of Mad river |
| Maddenville | PO | Huntingdon Co, PA | ||
| Maddox | PO | Hanover Co, VA | ||
| Madison | PV | Morris Co, NJ | ||
| Madison | PT | Somerset Co, ME | 1,769 | water by Kennebec river |
| Madison | PT | New Haven Co, CT | 1,729 | water by Long Island sound |
| Madison | PT | Madison Co, NY | 2,405 | water by head branches of Chenango river, Oriskany creek & Chenango canal |
| Madison | PO | Westmoreland Co, PA | ||
| Madison | T | Columbia Co, PA | 712 | water by Little Fishing & Mahoning creeks |
| Madison | T | Armstrong Co, PA | 1,151 | |
| Madison | T | Perry Co, PA | 1,292 | |
| Madison | PT | Lake Co, OH | 2,986 | water by Grand river |
| Madison | T | Clark Co, OH | 949 | |
| Madison | PT | Columbiana Co, OH | 1,406 | |
| Madison | T | Butler Co, OH | 2,242 | |
| Madison | T | Fayette Co, OH | 865 | |
| Madison | T | Franklin Co, OH | 2,480 | water by Alum, Big Walnut & Black Lick creeks |
| Madison | T | Fairfield Co, OH | 1,164 | |
| Madison | T | Guernsey Co, OH | 1,519 | |
| Madison | T | Jackson Co, OH | 1,515 | water by Symmes' creek |
| Madison | T | Licking Co, OH | 1,027 | water by Licking river & Ohio canal |
| Madison | T | Highland Co, OH | 1,163 | |
| Madison | PT | Montgomery Co, OH | 1,668 | |
| Madison | PT | Muskingum Co, OH | 1,047 | |
| Madison | T | Pickaway Co, OH | 886 | |
| Madison | T | Perry Co, OH | 988 | |
| Madison | PT | Richland Co, OH | 1,732 | |
| Madison | T | Sandusky Co, OH | 389 | |
| Madison | T | Scioto Co, OH | 1,367 | |
| Madison | PV | Rockingham Co, NC | ||
| Madison | PV, CH | Morgan Co, GA | seat of justice | |
| Madison | PV, City | Jefferson Co, IN | 7,908 | seat of justice, water by Ohio river |
| Madison | PT | Jefferson Co, IN | 3,193 | |
| Madison | T | Montgomery Co, IN | 651 | |
| Madison | T | Putnam Co, IN | 1,199 | |
| Madison | T | Lenawee Co, MI | 2,404 | |
| Madison | T | Sevier Co, AR | 350 | |
| Madison | T | Clarke Co, MO | ||
| Madison | T | Polk Co, MO | ||
| Madison | T | Livingston Co, MO | ||
| Madison | T | Johnson Co, MO | 668 | |
| Madison | PV | Monroe Co, MO | ||
| Madison | PV, CH | Madison Co, VA | seat of justice | |
| Madison | PV, CH | Madison Co, FL | ||
| Madison | PV, CH | Dane Co, WI | 1,871 | seat of justice, Capital of WI |
| Madison | PV | Livingston Co, MI | ||
| Madisonburgh | PO | Wayne Co, OH | ||
| Madisonborough | PO | Alachua Co, FL | ||
| Madison Centre | PO | Madison twp, Somerset Co, ME | ||
| Madison Cross Roads | PO | Madison Co, AL | ||
| Madison Mills | PO | Madison Co, VA | ||
| Madison Springs | PV | Madison Co, GA | site of salubrious mineral springs | |
| Madisonville | PV | Columbia twp, Hamilton Co, OH | ||
| Madisonville | PV, CH | Hopkins Co, KY | ||
| Madisonville | PV | Monroe Co, TN | ||
| Madisonville | PV | Ralls Co, MO | ||
| Madisonville | PV | St Tammany parish, LA | water by Chefonte river | |
| Madisonville | PV | Madison Co, MS | ||
| Madrid | PT | Franklin Co, ME | 404 | water by branches of Sandy river |
| Madrid | PT | St Lawrence Co, NY | 4,856 | water by Grass & St Lawrence rivers |