| Marty D Beagle Construction | Marty Dee Beagle | — | (408) 482 1572 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Matlock Construction | Karl Richard Matlock | — | (707) 834 0507 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Matthew Lewis Construction | Matthew Trent Lewis | — | (707) 572 7883 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Mattole Restoration Council-landscaping | Cassie Maria Pinnell | — | (707) 629 3514 | Windows, patio, painters | Petrolia · Humboldt County | — | — |
| Mattole Salmon Group | Campbell Lyman Thompson | — | (707) 629 3433 | Windows, patio, painters | Petrolia · Humboldt County | — | — |
| Mattole Valley Construction INC | Elizabeth Anne Webb | — | (707) 629 3556 | GC, remodel, ADU | Petrolia · Humboldt County | — | — |
| Maximum Construction | Timothy Max Mahony | — | (707) 223 0258 | GC, remodel, ADU | Miranda · Humboldt County | — | — |
| Mb Construction | Mark Alan Burdick | — | (707) 273 0394 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Mc Clure Construction | William Thomas Mc Clure | — | (707) 498 2965 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Mc Clurg's Flooring Specialist | Mc Clurg's Flooring Specialist | — | (707) 496 8847 | Other | Eureka · Humboldt County | — | — |
| Mc Combs Construction | Mark Alan Mc Combs | — | (707) 845 8789 | GC, remodel, ADU | Rio Dell · Humboldt County | — | — |
| Mc Kenny & Sons INC | Laurie Renee Mckenny | — | (707) 498 7681 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Mc Kenzie Construction | Gregory Hugh Mc Kenzie | office@mckenzieconstruction.com | (707) 768 5007 | GC, remodel, ADU | Hydesville · Humboldt County | — | — |
| Mccullough Construction & Associates INC | Dena Ann Mc Cullough | — | (707) 499 1471 | Other | Blue Lake · Humboldt County | — | — |
| Mccullough Construction INC | Hugh Macky Jr Mc Cullough | — | (707) 825 1014 | Windows, patio, painters | Arcata · Humboldt County | — | — |
| Mci | Gina Yvette Mobley | — | (707) 496 5699 | Other | Ferndale · Humboldt County | — | — |
| Mckeever Energy & Electric INC | Nathan Mckeever | — | (707) 407 6990 | Electricians | Arcata · Humboldt County | — | — |
| Mckinleyville Glass Co | Terry Alan Mc Cutchan | eben@eyebytes.com | (707) 839 2964 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Mckinnon's Roofing INC | Bradley Joe Mckinnon | mckinnonsroofing@gmail.com | (707) 572 4443 | Other roofers | Mc Kinleyville · Humboldt County | — | — |
| Mcmurray & Sons INC | Catherine Lea Minkema | — | (707) 443 3088 | Other roofers | Eureka · Humboldt County | — | — |
| Mel Brown Excavation And Paving | Mel Brown Excavation And Paving | — | (707) 498 8001 | Other | Bridgeville · Humboldt County | — | — |
| Melendez Construction | Nathan James Melendez | — | (707) 601 1689 | GC, remodel, ADU | Garberville · Humboldt County | — | — |
| Melkor Metal Fabrication LLC | James Davidpatrick Beurer | — | (734) 223 2784 | Other | Redway · Humboldt County | — | — |
| Mercer Fraser Company | Justin Edward Zabel | — | (707) 443 6371 | Other | Eureka · Humboldt County | — | — |
| Messina Electronics Support Services | Scott Alan Messina | — | (707) 440 9384 | Electricians | Eureka · Humboldt County | — | — |
| Meyer's Land Clearing INC | Jeffrey Russell Meyer | — | (707) 599 6741 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Michael A Mondragon Construction | Michael Anthony Mondragon | — | (707) 498 0104 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Michael Abercrombie Construction | Michael John Abercrombie | — | (707) 845 1962 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Michael Hoes Construction | Michael Valerie Hoes | — | (707) 498 0310 | GC, remodel, ADU | Bayside · Humboldt County | — | — |
| Michael Parent Const | Michael Parent Const | — | (707) 443 1188 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Michael Pillor Construction | Michael Allen Pillor | — | (707) 362 4216 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Michael Troyer | Michael Troyer | — | (707) 672 4853 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Michael U Matteri Construction | Michael Ugo Matteri | — | (707) 499 9986 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Michael Verbich Construction | Michael James Verbich | — | (707) 496 8007 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Mickey & Son's Construction LLC | Luis Angel Ramirez Moreno | — | (707) 599 2531 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Mike Norris | Mike Norris | — | (707) 445 1335 | Other | Eureka · Humboldt County | — | — |
| Mike St John Painting | Mike St John Painting | — | (707) 498 2995 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Miller Farms Nursery INC | Joan Loree Miller | — | (707) 839 1571 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Mills Builds INC | Jesse Nolan Mills | — | (707) 630 2230 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Model A Tile | Model A Tile | — | (707) 499 6718 | Other | Arcata · Humboldt County | — | — |