| Highlight Gallery | Highlight Gallery | — | (707) 937-3132 | Windows, patio, painters | Mendocino · Mendocino County | — | — |
| Higuera Construction | Higuera Carlos | — | (707) 884 1799 | GC, remodel, ADU | Gualala · Mendocino County | — | — |
| Hoffman Construction | Michael Thomas Hoffman | — | (707) 357 4117 | GC, remodel, ADU | Navarro · Mendocino County | — | — |
| Holguin Hardy Group | Edy Amavizca Holguin | — | (707) 291 9980 | GC, remodel, ADU | Gualala · Mendocino County | — | — |
| Hollifield Construction | Todd William Hollifield | — | (707) 459 3558 | HVAC | Willits · Mendocino County | — | — |
| Hollow Tree Cabinet Company INC | Douglas Gerhard Myers | — | (707) 462 6315 | Other | Ukiah · Mendocino County | — | — |
| Holtz Trucking & Construction | Eric Von Holtz | — | (707) 972 6279 | Other | Ukiah · Mendocino County | — | — |
| Hometown Store INC | Kenneth Harley Foster | — | (707) 462 7757 | Other | Ukiah · Mendocino County | — | — |
| Inglenook Electric | David John Gealey | — | (707) 813 0048 | Electricians | Fort Bragg · Mendocino County | — | — |
| Integrity Painting | Integrity Painting | — | (707) 391 4012 | Windows, patio, painters | Ukiah · Mendocino County | — | — |
| Intercounty Mechanical & Electrical INC | Aimee Laraine Shields | — | (707) 462 9800 | HVAC | Ukiah · Mendocino County | — | — |
| Irving's Custom Painting | Irving's Custom Painting | — | (707) 357 8904 | Windows, patio, painters | Fort Bragg · Mendocino County | — | — |
| Ivan Shipley Electric | Ivan Jon Shipley | — | (707) 489 5353 | Electricians | Ukiah · Mendocino County | — | — |
| J & L Painting | J & L Painting | — | (707) 272 5137 | Windows, patio, painters | Ukiah · Mendocino County | — | — |
| J & S General Engineering Solutions LLC | Stacey Marie Donahoo | — | (707) 481 7568 | Other | Ukiah · Mendocino County | — | — |
| J A Construction | Joel Abraham Blocksom | — | (707) 972 6271 | GC, remodel, ADU | Littleriver · Mendocino County | — | — |
| J Adams Construction | John William Adams | — | (707) 357 2849 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| J B Smith Construction | Justin Brian Smith | — | (707) 357 6438 | GC, remodel, ADU | Willits · Mendocino County | — | — |
| J C Construction | John Jerry Conchola | — | (707) 489 9787 | GC, remodel, ADU | Talmage · Mendocino County | — | — |
| J Howell Fine Art | J Howell Fine Art | gallery@jhowellfineart.com | (707) 293-7426 | Windows, patio, painters | Mendocino · Mendocino County | — | — |
| J K P Builders | J K P Builders | — | (707) 841 7501 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| J R S Construction | Robert Dennis Scroggin | — | (707) 245 5668 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| J S Morris Construction INC | J S Morris Construction INC | — | (707) 472 0504 | Other | Ukiah · Mendocino County | — | — |
| J Schmidt Construction INC | John Ray Schmidt | info@jschmidtconstruction.com | (707) 884 9574 | GC, remodel, ADU | Gualala · Mendocino County | — | — |
| J T Contracting | Jason Boster Tidd | — | (707) 367 3291 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| J W Morrison INC | John Walter Morrison | — | (707) 984 8858 | Tree | Laytonville · Mendocino County | — | — |
| Jack Kronfeld Construction | Jack Joseph Kronfeld | — | (707) 813 1146 | GC, remodel, ADU | Mendocino · Mendocino County | — | — |
| Jackson Hantzsche | Jackson Hantzsche | — | (707) 882 1695 | Windows, patio, painters | Manchester · Mendocino County | — | — |
| Jacobson Construction | Richard Wayne Jacobson | — | (707) 884 9520 | Other roofers | Fort Bragg · Mendocino County | — | — |
| Jaime Ceja General Construction | Ceja Jaime | — | (707) 376 6613 | GC, remodel, ADU | Willits · Mendocino County | — | — |
| Jan Christian Jakob | Jan Christian Jakob | — | (707) 937 5922 | GC, remodel, ADU | Mendocino · Mendocino County | — | — |
| Jay T Fraser General Building Contractor | Jay Terry Fraser | — | (707) 489 6896 | GC, remodel, ADU | Willits · Mendocino County | — | — |
| Jbs Construction INC | Jesse Brandon Senften | — | (707) 478 3295 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| Jd General Engineering Corp | John Gilbert Duran | — | (707) 621 0578 | Other | Ukiah · Mendocino County | — | — |
| Jeanne Carol Grant | Jeanne Carol Grant | — | (805) 479 9139 | Windows, patio, painters | Redwood Valley · Mendocino County | — | — |
| Jeff Forbes Construction | Jeffrey Scott Forbes | — | (530) 624 6259 | GC, remodel, ADU | Mendocino · Mendocino County | — | — |
| Jeff G Trouette Plumbing | Jeff G Trouette Plumbing | — | (707) 462 8216 | Other | Ukiah · Mendocino County | — | — |
| Jeff Rhodes Construction | Jeffrey Fred Rhodes | — | (707) 391 3070 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| Jeffrey S Green | Jeffrey S Green | — | (707) 964 7346 | Other | Fort Bragg · Mendocino County | — | — |
| Jeremiah Johnson | Jeremiah Johnson | — | (707) 357 4959 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |