| Chicago, Rock Island and Pacific Railroad | Chicago | 1866 |
| Chikara | Philadelphia | 2002 |
| Chipotle Mexican Grill | Denver, Newport Beach | July 13, 1993 |
| Choice Hotels | Rockville, Silver Spring | 1939 |
| Church & Dwight | Ewing Township | 1846 |
| Circle | Boston | October 2013 |
| Circuit City Stores | Richmond | 1984 |
| Cisco | San Jose | 1984 |
| Citadel LLC | Miami | 1990 |
| Citgo | Houston | 1910 |
| Citibank | Sioux Falls, New York City | 1865 |
| Citizens Financial Group | Providence | 1954 |
| CLS Group | New York | 2002 |
| CodeGear | Scotts Valley, California | 2006 |
| Cognex Corporation | Natick | 1981 |
| Cole Haan | Greenland | 1928 |
| Coleco | West Hartford | 1932 |
| Columbia Sportswear Company | Cedar Mill | 1938 |
| Combustion Engineering | Stamford | 1912 |
| Comcast | Philadelphia | June 28, 1963 |
| Compaq | Houston | February 16, 1982 |
| Conair Corporation | East Windsor Township | 1959 |
| Concentrix | Fremont | 2004 |
| Concord | Beverly Hills | 1973 |
| Conexant | Irvine | 1999 |
| Consol Energy | Pittsburgh | 1991 |
| Coors Brewing Company | Golden | 1873 |
| Cord Automobile | United States | 1929 |
| CoreCivic | Nashville | 1983 |
| CoreWeave | Roseland | 2017 |
| Coty | New York City | 1904 |
| CouchSurfing | San Francisco | April 2, 2003 |
| Crackle | Culver City | July 2007 |
| Creative Micro Designs | East Longmeadow | 1987 |
| Credo Reference | Boston | 1999 |
| CrowdStrike | Austin | August 29, 2011 |
| Crunchbase | San Francisco | July 2007 |
| Currier and Ives | New York City | 1835 |
| Cushman & Wakefield | New York City | 1917 |
| CVS Pharmacy | Woonsocket | 1963 |
| Cyan Worlds | Wilmington, Mead | 1987 |
| Cypress Semiconductor | San Jose | 1982 |
| Cyrix | Richardson | 1988 |
| D'Addario | Farmingdale | 1973 |
| Dallas Semiconductor | Dallas | February 1, 1984 |
| DallasNews Corporation | Dallas | 2008 |
| Dana Corporation | Toledo | 1904 |
| Danjaq | Santa Monica | 1962 |