| MacKinnon, Anne, Casper Star-Tribune reporter and editor | Kerry Drake |
| Magill, Ada, Oregon Trail grave of | WyoHistory.org |
| Marbleton, Wyoming | Ann Chambers Noble |
| Marking historic sites, history of in Wyoming | Kylie Louise McCormick, The Wyoming Monuments and Markers Program |
| Martin, Joe, lynching of | Kim Viner |
| Martin’s Cove, events of 1856 | Annette Hein |
| Martin’s Cove, Mormon Church Acquisition of | Annette Hein |
| Mathew Campfield Park | |
| Matthew Shepard memorial bench | |
| Maynardier, Col. Henry E., Fort Laramie commander | Tom Rea |
| McCoy, Tim and Ed Farlow with Wind River Indians on stage and screen | Rebecca Hein |
| McCraken, Tracy, Cheyenne newspaper publisher | Kerry Drake |
| McGee, Gale, U.S. senator 1958-1976. | Rodger McDaniel |
| Mead, Elwood and Wyoming's water law | Anne MacKinnon |
| Medicine Bow Museum | |
| Medicine Bow Peak Plane Crash Memorial Plaque | |
| Medicine Bow Peak, plane crash into, 1955 | Thaddeus Mast |
| Medicine Lodge | WyomingHeritage.org |
| Medicine Lodge Archaeological Site | |
| Medicine Wheel | Fred Chapman |
| Medicine Wheel | |
| Meeks, Bub | Dick Blust, Jr. |
| Meeteetse | |
| Mercado, Felix on sugar-beet farming in the Big Horn Basin | Washakie Museum and Cultural Center |
| Mercer, Asa Shinn, life and newspaper career of | Rebecca Hein |
| Metz, Percy, Big Horn Basin judge and trial lawyer | John W. Davis |
| Mexican Hill, Oregon-California Trail site | Randy Brown |
| Mexican Punitive Expedition, Wyoming National Guard and, 1916 | Carl V. Hallberg |
| Milholland, Inez, suffragist and orator | Lesley Wischmann |
| Military horses, Wyoming as breeding ground for, 1897-1949 | Rebecca Hein |
| Miller, Alfred Jacob, painter of the fur trade | Chavawn Kelley |
| Miller, Leslie | Wyoming State Archives |
| Mineral Leasing Act 1920 | Samuel Western |
| Mineral Leasing Act, 1970s amendments to | Samuel Western |
| Mineral Severance Tax | Sarah Gorin |
| Mineral Trust Fund, Permanent Wyoming | Sarah Gorin |
