| Comscore | Reston | 1999 |
| Conair Corporation | Municipio de East Windsor | 1959 |
| Concentrix | Fremont | 2004 |
| Conn-Selmer | Elkhart | 1909 |
| ConocoPhillips | Houston | 1875 |
| Consol Energy | Pittsburgh | 1991 |
| Consolidated Aircraft | San Diego | 1923 |
| Convergys | Cincinnati | 1998 |
| Coors Brewing Company | Golden | 1873 |
| Cord | Estados Unidos | 1929 |
| Corning Inc. | Corning | 1851 |
| Corporation for Public Broadcasting | Washington D. C. | 7 de noviembre de 1967 |
| Coty Inc. | Nueva York | 1904 |
| CoverGirl | Maryland | 1961 |
| Coverity | San Francisco | noviembre 2002 |
| Cox | Phoenix | 1962 |
| Crackle | Culver City | julio 2007 |
| Crayola | Municipio de Forks | 1885 |
| Creative Micro Designs | East Longmeadow | 1987 |
| CREDO reference | Boston | 1999 |
| Cricket Wireless | San Diego | 1999 |
| CrossFit | Santa Cruz | 2000 |
| Crystal Cruises | Los Ángeles | 1988 |
| CSX Corporation | CSX Transportation Building | 1 de noviembre de 1980 |
| Culligan | Rosemont | 1936 |
| Cummins Inc. | Columbus | 1919 |
| Currier & Ives | Nueva York | 1835 |
| Curtiss-Wright | Charlotte | 1929 |
| CVS Pharmacy | Woonsocket | 1963 |
| Cyan Worlds | Wilmington, Mead | 1987 |
| Cygnus Solutions | — | 13 de noviembre de 1989 |
| Cyrix | Richardson | 1988 |
| D'Addario | Farmingdale | 1973 |
| D23 | Burbank | 2009 |
| Dana Incorporated | Toledo | 1904 |
| Danelectro | Camarillo | 1947 |
| DataStax | Santa Clara | abril 2010 |
| DC Universe | Burbank | 2018 |
| DDB Worldwide | Chicago, San Francisco, Londres | 1949 |
| De Arby | Sandy Springs | 1964 |
| Deere & Company | Moline | 1868 |
| Dell | Round Rock | 7 de septiembre de 2016 |
| Dell Technologies | Round Rock | 7 de septiembre de 2016 |
| Delmark Records | — | 1953 |
| Delta Air Lines | Atlanta | 17 de junio de 1929 |
| Detroit Electric Car Company | Detroit | 1907 |
| Diamond-Star Motors | — | octubre 1985 |
| Dickies | Fort Worth | 1918 |