| Corey Matteson Pools | Corey Matteson Pools | — | (949) 554 5119 | Pool | Laguna Niguel · Orange County | — | — |
| Corey Plastering | Corey Plastering | — | (714) 785 9563 | Other | Fullerton · Orange County | — | — |
| Coria Construction INC | William Coria | info@coriaconstruction.com | (714) 797 3995 | GC, remodel, ADU | Fullerton · Orange County | — | — |
| Cornejo's Glass | Cornejo's Glass | — | (949) 310 2400 | Windows, patio, painters | Costa Mesa · Orange County | — | — |
| Cornelius Construction | Jason Wayne Cornelius | — | (951) 259 8284 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| Cornell Design | Cornell Design | — | (714) 620 6077 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Cornell Design & Decorating INC | Cornell Pintilie | — | (714) 620 6077 | Windows, patio, painters | Anaheim · Orange County | — | — |
| Cornerstone Builders Co | Angello Titus Tina | — | (714) 240 3701 | GC, remodel, ADU | Irvine · Orange County | — | — |
| Cornerstone Carpet And Floors INC | James Kenneth Dillon | — | (562) 799 8200 | Other | Los Alamitos · Orange County | — | — |
| Cornerstone Construction | Earl James Iii Reeves | gwebb@cornerstone-construction.com | (832) 259-2520 | GC, remodel, ADU | Orange · Orange County | — | — |
| Cornerstone Construction | Steven Gia Hoang | gwebb@cornerstone-construction.com | (832) 259-2520 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Cornerstone Construction & Landscape | Nhat Hong Tran | — | (714) 880 2620 | Electricians | Stanton · Orange County | — | — |
| Cornerstone Construction & Roofing | Nhat Hong Tran | — | (714) 206 4320 | Other roofers | Stanton · Orange County | — | — |
| Cornerstone Construction Company | Luis Ismael Jr Rodriguez | gwebb@cornerstone-construction.com | (832) 259-2520 | GC, remodel, ADU | Newport Beach · Orange County | — | — |
| Cornerstone Constuction And Property Services LLC | Frank Harold Erichson | — | (949) 369 1979 | GC, remodel, ADU | San Clemente · Orange County | — | — |
| Cornerstone Custom Patio Covers INC | Bradley Scott Hisgen | — | (714) 964 1561 | GC, remodel, ADU | Huntington Beach · Orange County | — | — |
| Cornerstone Electrical Services INC | David Michael Ii Tschann | — | (714) 244 7867 | Electricians | Anaheim · Orange County | — | — |
| Cornerstone Family Investment INC | Fereidoon Fred Saedi | — | (949) 481 6614 | GC, remodel, ADU | Laguna Niguel · Orange County | — | — |
| Cornerstone Group | Jing Guo | info@cornerstonegroup.com | (949) 878 7171 | GC, remodel, ADU | Lake Forest · Orange County | — | — |
| Cornerstone Landscape Care INC | Antonio Jr Gomez | — | (714) 654 2279 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| Cornerstone Remodel | Dat Thanh Nguyen | — | (714) 251 1223 | GC, remodel, ADU | Yorba Linda · Orange County | — | — |
| Cornerstone Remodeling INC | Douglas James Grant | — | (800) 998 8983 | GC, remodel, ADU | Cypress · Orange County | — | — |
| Corona Stone & Tile INC | Walter Ernesto Chavez | — | (714) 905 4869 | Other | Santa Ana · Orange County | — | — |
| Corporate Builders | Corporate Builders | — | (949) 279 0859 | GC, remodel, ADU | Trabuco Canyon · Orange County | — | — |
| Corporate Business Interiors INC | Brian Joseph Bonet | — | (949) 225 3900 | GC, remodel, ADU | Newport Beach · Orange County | — | — |
| Corporate Modular Services INC | George Ayala | — | (833) 821 7100 | Other | Santa Ana · Orange County | — | — |
| Corradini Corp | Randall Scott Nunnelly | — | (323) 221 3191 | Other | Costa Mesa · Orange County | — | — |
| Corral Builders INC | Joe Anthony Iv Corral | — | (949) 415 9056 | GC, remodel, ADU | Costa Mesa · Orange County | — | — |
| Correa Doors & Hardware INC | Jose Miguel Correa | — | (949) 662 3030 | Other | Irvine · Orange County | — | — |
| Correa's Landscape | Correa's Landscape | — | (714) 883 8551 | Windows, patio, painters | Westminster · Orange County | — | — |
| Cortes & Family Masonry | Espino Filiberto Cortes | — | (714) 583 5263 | Windows, patio, painters | Santa Ana · Orange County | — | — |
| Cortes Landscape Services | Guzman Heriberto Cortes | — | (714) 650 3391 | Windows, patio, painters | Garden Grove · Orange County | — | — |
| Corvus Corp | Jerrad James Long | info@corvus.com | (951) 833 7200 | GC, remodel, ADU | Tustin · Orange County | — | — |
| Cory A Bersch General Contractor | Cory A Bersch General Contractor | — | (714) 309 1873 | GC, remodel, ADU | Santa Ana · Orange County | — | — |
| Cory James Olson | Cory James Olson | — | (909) 772 4277 | Electricians | Aliso Viejo · Orange County | — | — |
| Cosco Fire Protection | Vincent Ray Jr Vine | — | (949) 542 8200 | Electricians | Mission Viejo · Orange County | — | — |
| Cosmos Air Comfort Zone | Cosmos Air Comfort Zone | — | (714) 650 9960 | HVAC | Anaheim · Orange County | — | — |
| Cost Less Electric | Matthew Aaron Williams | — | (562) 587 2859 | Electricians | La Habra · Orange County | — | — |
| Costa Mesa Garden | Marcelino C Duran | — | (949) 230 3934 | Windows, patio, painters | Costa Mesa · Orange County | — | — |
| Costa Mesa Lock & Key | Thomas Wayne Halliburton | — | (714) 545 3246 | Other | Costa Mesa · Orange County | — | — |