| Mammoth Bluesapalooza | Mammoth Lakes | CA | United States | August | 1st Weekend | 4 Days | Variety | Music |
| Mandolin Farm Bluegrass Festival | Grayson | KY | United States | July | 1st Weekend | 3 Days | Bluegrass | Music |
| Mansfield Jamfest | Mansfield | OH | United States | June | 2nd Weekend | 3 Days | Bluegrass | Music |
| Marana Bluegrass & Acoustic Music Festival | Marana | AZ | United States | March | 2nd Weekend | 3 Days | Bluegrass and Acoustic Music | Music |
| Mariposa Folk Festival | Granville | OH | United States | July | 1st Weekend | 3 Days | Folk, with strong representation of Americana, singer-songwriter, and roots music. | Music |
| Marshall Bluegrass Festival | Marshall | MI | United States | July | 3rd Weekend | 7 Days | Bluegrass | Music |
| Maui Songwriters Festival | Maui | HI | United States | January | 2nd Weekend | 4 Days | Singer-songwriter, Americana, country, folk (with a focus on Nashville songwriters) | Music |
| Maury River Fiddlers Convention | Buena Vista | VA | United States | June | 3rd Weekend | 3 Days | Bluegrass | Music |
| May on the Mountain | Henagar | AL | United States | May | 2nd Saturday | 1 Day | Bluegrass | Music |
| Mayhaw Music Festival | Cottonwood | AL | United States | October | 1st Saturday | 1 Day | Bluegrass | Music |
| Mayville Bluegrass Festival | Mayville | NY | United States | August | 3rd Weekend | 1 Day | Bluegrass | Music |
| MeadowGrass Music Festival | Colorado Springs | CO | United States | May | Memorial Day Weekend | 3 Days | Bluegrass | Music |
| Memorial Day Weekend Bluegrass Festival | Kendallville | IN | United States | June | Memorial Day Weekend | 4 Days | Bluegrass | Music |
| Mempho Fest | Memphis | TN | United States | September | 4th Weekend | 3 Days | Blues, Indie, Rock | Music |
| MerleFest | Wilkesboro | NC | United States | April | 4th Weekend | 4 Days | Bluegrass | Music |
| Mesa Singer Songwriter Festival | Mesa | AZ | United States | July | 2nd Weekend | 3 Days | Singer/songwriting | Music |
| Metamora Music Festival | Metamora | IN | United States | September | 1st Weekend | 2 Days | Variety | Music |
| Miche Fest | Chicago | IL | United States | July | 2nd Weekend | 2 Days | Latin, R&B | Music |
| Mid-Winter Bluegrass Festival | Denver | CO | United States | February | 2nd Weekend | 3 Days | Bluegrass | Music |
| Midsummer Bluegrass Music Festival | Manitowish Waters | WI | United States | July | 4th Weekend | 4 Days | Bluegrass | Music |
| Mighty Roots Music Festival | Stovall | MS | United States | September | 2nd Weekend | 2 Days | Americana, with strong roots in Blues, Folk, Rock, and Country, featuring singer-songwriter artists. | Music |
| Milaca RecFest Bluegrass Festival | South Hiram | ME | United States | July | 4th Weekend | 4 Days | Bluegrass | Music |
| Milan Bluegrass Festival | Milan | MI | United States | July | 2nd Weekend | 3 Days | Bluegrass | Music |
| Miles City Bluegrass Festival | Miles City | MT | United States | September | 3rd Weekend | 3 Days | Bluegrass | Music |
| Mine Made Adventure Park Bluegrass Festival | Leburn | KY | United States | June | 1st Weekend | 3 Days | Bluegrass | Music |
| Minnesota Bluegrass Fall Jam | Plymouth | MN | United States | November | 2nd Weekend | 3 Days | Bluegrass | Music |
| Minnesota Homegrown Kickoff (jamming Only) | Richmond | MN | United States | June | 1st Weekend | 3 Days | Bluegrass | Music |
| Minnesota Music Festival | Minneapolis | MN | United States | May | 2nd Weekend | 2 Days | Various genres | Music |
| Minnesota Yacht Club Festival | Saint Paul | MN | United States | July | 3rd Weekend | 2 Days | Alternative, Country, Rock, Pop | Music |
| Mississippi Delta Blues Festival | Greenville | MS | United States | August | Varies | 3 Days | Blues, with influences of Americana, Roots, and Gospel. | Music |
| Missouri River Bluegrass Festival | Center | ND | United States | June | 3rd Weekend | 2 Days | Bluegrass | Music |
| Mitch & Cindy’s Bluegrass Music Festival | Cortland | OH | United States | June | Memorial Day Weekend | 3 Days | Bluegrass | Music |
| MMRBQ | Camden | NJ | United States | September | 3rd Weekend | 1 Day | Rock, Indie, Alternative, and Other Genres | Music |
| MN Bluegrass & Old-Time Music Festival | Richmond | MN | United States | August | 2nd Weekend | 4 Days | Bluegrass and Old-Time | Music |
| Moccasin Creek Festival | Effingham | IL | United States | June | 3rd Weekend | 4 Days | Americana, country, folk | Music |
| Mohican Bluegrass Festival | Glenmont | OH | United States | September | 2nd Weekend | 3 Days | Bluegrass | Music |
| Mondegreen | Dover | DE | United States | August | 3rd Weekend | 4 Days | Jam | Music |
| Monterey Jazz Festival | Monterey | CA | United States | September | 4th Weekend | 3 Days | Jazz | Music |
| Moon Crush Cowboy Moon | Miramar Beach | FL | United States | November | 1st Weekend | 3 Days | Country | Music |
| Moon River Festival | Chattanooga | TN | United States | September | Last Weekend | 3 Days | Folk, with strong representation of Americana, singer-songwriter, and roots music. This festival offers a more intimate setting focused on these genres. | Music |
| Moondance Jam | Walker | MN | United States | July | 3rd Weekend | 3 Days | Jam, Rock | Music |
| Moonshiner’s Ball | Mount Vernon | KY | United States | October | 2nd Weekend | 4 Days | Bluegrass, Jam, Rock | Music |
| Moorefields Bluegrass Festival | Hillsborough | NC | United States | October | 2nd Saturday | 1 Day | Bluegrass | Music |
| Morris Bluegrass Festival | Morris | CT | United States | July | 1st Weekend | 1 Day | Bluegrass | Music |
| Mosswood Meltdown | Oakland | CA | United States | May | 3rd Weekend | 2 Days | Indie | Music |
| Mount Airy Bluegrass & Old-Time Fiddlers Convention | Mount Airy | NC | United States | June | 2nd Weekend | 2 Days | Bluegrass | Music |
| Mount Airy Fiddlers Convention | Mount Airy | NC | United States | June | 2nd Weekend | 2 Days | Old-Time, Bluegrass | Music |
| Mount St. Helens Bluegrass Festival | Toledo | WA | United States | August | 2nd Weekend | 3 Days | Bluegrass | Music |
| Mountain City Fiddlers Convention | Mountain City | TN | United States | September | 1st Weekend | 1 Day | Old-Time, Bluegrass | Music |
| Mountain Heritage Arts & Crafts Festival | Kearneysville | WV | United States | September | 4th Weekend | 2 Days | Bluegrass | Music |
| Mountain Magic In Fall Bluegrass, Antiques & Crafts Festival | Buchanan | VA | United States | October | 1st Weekend | 1 Day | Bluegrass | Music |
| Mountain Song Festival | Brevard | NC | United States | September | 1st Weekend | 2 Days | Bluegrass | Music |
| Mountain Stage New Song Festival Charleston | Charleston | WV | United States | September | Labor Day Weekend | 3 Days | Primarily singer-songwriter, with strong representation of Americana, folk, and roots music, featuring a mix of established and emerging artists. | Music |
| Mountain USA Festival | Gatlinburg | TN | United States | August | 4th Weekend | 3 Days | Country, Bluegrass, Folk, Americana | Music |
| Mountain View Bluegrass Festival | Mountain View | AR | United States | November | 1st Weekend | 3 Days | Bluegrass | Music |
| Mountain View Bluegrass Festival | Mountain View | AR | United States | November | 1st Weekend | 3 Days | Bluegrass | Music |
| Mr. B’s Bluegrass Festival | Woodford | VA | United States | May | 1st Weekend | 3 Days | Bluegrass | Music |
| Muscle Shoals Songwriting Festival | Muscle Shoals | AL | United States | November | 1st Weekend | 3 Days | Singer-Songwriter, Americana, Folk and Country | Music |
| Music & Art in the Park | New Cumberland | WV | United States | April | 2nd Weekend | 1 Day | Bluegrass | Music |
| Music at The Intersection | St. Louis | MO | United States | September | 2nd Weekend | 2 Days | Blues, Hip Hop, Jazz, R&B, Rock, Soul | Music |
| Musikfest | Bethlehem | PA | United States | August | 1st Weekend | 10 Days | Country, Rock | Music |
