| Niko Kennedy | Niko Kennedy | — | (805) 452 7847 | GC, remodel, ADU | Willits · Mendocino County | — | — |
| Nmp Construction | Neil Preston Peterson | — | (509) 951 8342 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| Non Electrical Banners & Signs | Chad Pierre Goodin | — | (707) 462 7853 | Other | Ukiah · Mendocino County | — | — |
| Nor-cal Compliance INC | Joel Edward Hendrix | — | (707) 489 8992 | Other | Ukiah · Mendocino County | — | — |
| Nor-cal Gutter Services | Jose Manuel Hernandez Martinez | — | (707) 391 0354 | Other | Ukiah · Mendocino County | — | — |
| Norbury Construction | Billy Dean Norbury | — | (707) 485 4230 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| Norcal Real Solutions | Norcal Real Solutions | — | (510) 846 4447 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Norcal Seamless Gutters | Norcal Seamless Gutters | — | (707) 974 8875 | Other | Ukiah · Mendocino County | — | — |
| North Bay Construction Contractors | Eduardo Nieto | — | (707) 671 3253 | GC, remodel, ADU | Willits · Mendocino County | — | — |
| North Bay Tile Restoration | North Bay Tile Restoration | — | (707) 328 1223 | Restoration | Ukiah · Mendocino County | — | — |
| North Coast Construction Concepts | Kelley Jordan Cochran | — | (707) 695 3825 | GC, remodel, ADU | Manchester · Mendocino County | — | — |
| North Coast Energy Services Incorporated | Daniel Lee Mc Queen | — | (707) 463 0303 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| North Coast Floor Store INC | Lyndia Joyce Pyeatt | — | (707) 964 8889 | Other | Fort Bragg · Mendocino County | — | — |
| North Coast Painter | North Coast Painter | — | (707) 569 4689 | Windows, patio, painters | Fort Bragg · Mendocino County | — | — |
| North Coast Plumbing Heating And Sheet Metal INC | Campbell Allan Smith | — | (707) 964 2783 | HVAC | Fort Bragg · Mendocino County | — | — |
| North Coast Restoration | Christopher Wayne Matson | info@northcoastrestoration.com | (707) 962 7149 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| North Country Balconies | North Country Balconies | — | (707) 272 8086 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| North Court Construction | Gary Matthew Mcasey | — | (707) 272 3315 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| North State Construction | Mark Kevin Anderson | — | (707) 355 1440 | GC, remodel, ADU | Potter Valley · Mendocino County | — | — |
| Northcoast Artists Gallery | Northcoast Artists Gallery | — | (707) 964-8266 | Windows, patio, painters | Fort Bragg · Mendocino County | — | — |
| Northern Countertops | Northern Countertops | — | (707) 467 3969 | Other | Ukiah · Mendocino County | — | — |
| Northern Plumbing | Northern Plumbing | — | (707) 513 3907 | Other | Ukiah · Mendocino County | — | — |
| Northwest Construction INC | Larry Joe Brooks | — | (707) 272 7957 | Other | Redwood Valley · Mendocino County | — | — |
| Novoa Construction | Juan Gabriel Novoa | — | (707) 391 5669 | GC, remodel, ADU | Redwood Valley · Mendocino County | — | — |
| Noyo Forestry LLC | Gonzalo Sanchez | eben@eyebytes.com | (707) 734 0619 | Tree | Fort Bragg · Mendocino County | — | — |
| O T S Welding | O T S Welding | — | (707) 462 0660 | Other | Ukiah · Mendocino County | — | — |
| Oaktree Construction | Helio Cen | — | (707) 357 5872 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Ocean Construction Company | Cristopher Gene Grosjean | — | (707) 357 4817 | GC, remodel, ADU | Westport · Mendocino County | — | — |
| Ocean Painting | Ocean Painting | — | (707) 684 6071 | Windows, patio, painters | Gualala · Mendocino County | — | — |
| Ohlandt Construction INC | Michael Andrew Ohlandt | — | (707) 357 2225 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Ohm Renewable Power | Ohm Renewable Power | — | (510) 508 5539 | Electricians | Comptche · Mendocino County | — | — |
| Ojv Construction | Jacinto Villasenor Oscar | contact@ojvconstruction.com | (707) 391 9902 | GC, remodel, ADU | Ukiah · Mendocino County | — | — |
| Olenik Fence Co | John Eric Sundstrom | johnsundstrom354@att.net | (707) 489 1394 | Other | Willits · Mendocino County | — | — |
| Oliver Construction | William Shane Oliver | — | (707) 272 0070 | GC, remodel, ADU | Covelo · Mendocino County | — | — |
| On Point Tree Care | On Point Tree Care | info@mendowebdesign.com | (707) 472 8986 | Other | Willits · Mendocino County | — | — |
| Oro Roofing | Antonio Reyna Garcia | ororeliableroofing@gmail.com | (707) 962 7077 | Other roofers | Fort Bragg · Mendocino County | — | — |
| Oropeza Construction | Jose Catarino Jr Oropeza | — | (707) 684 9756 | GC, remodel, ADU | Gualala · Mendocino County | — | — |
| Orozco Construction | Sergio Camacho Orozco | — | (707) 367 2453 | GC, remodel, ADU | Manchester · Mendocino County | — | — |
| Orsi Construction | Jason Elvin Orsi | — | (707) 409 5083 | GC, remodel, ADU | Fort Bragg · Mendocino County | — | — |
| Ortega Brothers General Engineering | Ortega Brothers General Engineering | — | (707) 367 1478 | Other | Ukiah · Mendocino County | — | — |