| Chemical Bank | business | Midland, New York City | 1954 |
| Chevrolet | car brand, automobile manufacturer | Detroit | November 3, 1911 |
| Chicago Public Schools | school district in the United States | Chicago | — |
| Chicago The Musical Ambassador Theater | Broadway theatre, theatre building, movie theater | — | February 11, 1921 |
| Chicago, Burlington and Quincy Railroad | railway company | Chicago | 1856 |
| Chick-fil-A | fast food restaurant chain | Georgia | 1946 |
| Chikara | business, professional wrestling promotion | Philadelphia | 2002 |
| Choate Rosemary Hall | boarding school, organization | Wallingford | 1890 |
| Christie's | educational institution, organization, auction house | New York City, London | 1766 |
| Chrome Holding Co. | business, enterprise | South San Francisco | April 2006 |
| Chronicle Books | book publisher, publishing house | San Francisco | 1967 |
| CHS Inc. | business, gas station chain, public company | Inver Grove Heights | 1931 |
| Chuck E. Cheese | indoor play space, restaurant chain, pizzeria chain, public company | Irving | May 17, 1977 |
| Church's Texas Chicken | fast food restaurant chain, restaurant chain | Sandy Springs | April 17, 1952 |
| Cinemark | cinema chain, public company | Plano | 1984 |
| Cinematronics | video game developer | El Cajon | 1975 |
| Cinemaware | video game publisher, video game developer | Burlingame | 1986 |
| Circuit City Stores | business, enterprise | Richmond | 1984 |
| Cirrus Aircraft Corporation | aerospace manufacturer | Duluth | 1984 |
| CIT Group | business, public company | New York City | 1908 |
| Citibank | bank, business, financial institution, credit institution | Sioux Falls, New York City | 1865 |
| Citizens Financial Group | bank, business, public company | Providence | 1954 |
| Citrix Systems | software company, business, enterprise, public company | Fort Lauderdale | 1989 |
| City University of New York | state university system, state agency of New York, urban university, public university | New York City | 1961 |
| Claremont Graduate University | private not-for-profit educational institution, private university | — | 1925 |
| Clark Atlanta University | historically black college or university, private not-for-profit educational institution, private university | — | September 19, 1865 |
| Clinique Laboratories, LLC | cosmetics, business, subsidiary company | New York | 1968 |
| Clinton Presidential Center | Presidential libraries system, museum | — | 2004 |
| Cloudflare | technology company, online service, content delivery network, public company | San Francisco | July 17, 2009 |
| ClubJenna | television production company, pornographic film studio | Scottsdale | 2000 |
| CME Group | stock exchange, business, enterprise, public company | Chicago, London | July 12, 2007 |
| Codecademy | open educational resource, Virtual learning environment, website, business | New York City | 2011 |
| CodeGear | business, enterprise | Scotts Valley, California | 2006 |
| Cognizant Technology Solutions | technology company, enterprise, public company | Teaneck | 1994 |
| Coinbase | cryptocurrency exchange, digital currency exchanger, business, public company, payment system | San Francisco | June 20, 2012 |
| Colby College | private not-for-profit educational institution, liberal arts college in the United States | Waterville | 1813 |
| Coldwell Banker | business, enterprise | Cairo, Madison | August 27, 1906 |
| Colgan Air | regional airline | Memphis | 1991 |
| Colgate-Palmolive Company | business, public company | New York City | 1806 |
| College of Charleston | liberal arts college, public educational institution of the United States, university | — | 1770 |
| College of the Holy Cross | liberal arts college, private not-for-profit educational institution, university | Worcester | 1843 |
| College of William & Mary | public educational institution of the United States, public research university | Williamsburg | 1693 |
| College of Wooster | liberal arts college, college, Colleges That Change Lives, private not-for-profit educational institution | Wooster | 1866 |
| Collins Aerospace | defense contractor, aerospace manufacturer | Charlotte | 2018 |
| Colorado College | liberal arts college, private not-for-profit educational institution | Colorado Springs | 1874 |
| Colorado Fuel and Iron | business | Colorado | — |
| Colorado State University | public educational institution of the United States, land-grant university, public research university | — | 1870 |
| Colt's Manufacturing Company | business, subsidiary company, enterprise | West Hartford | 1855 |