| R. J. Reynolds Tobacco Company | business, enterprise | Winston-Salem | 1874 |
| Radford University | public educational institution of the United States, university | — | 1910 |
| RadioShack | group of companies, electronics store chain, public company | Fort Worth | 1921 |
| Radisson Blu | hotel chain | Brussels metropolitan area | 1994 |
| Radisson Hotel Group | privately held company, hotel chain, business | Minnetonka | 1962 |
| Raising Cane's Chicken Fingers | fast food restaurant chain, restaurant chain, business | Baton Rouge | 1996 |
| Ralston Purina | trademark, business | St. Louis | 1894 |
| Ram Trucks | car brand, division, automobile manufacturer | Auburn Hills | 2010 |
| Ramada | hotel chain, business, company | Phoenix | 1953 |
| Rambus | business, enterprise, public company | Sunnyvale | 1990 |
| Rankin/Bass Animated Entertainment | television production company | New York City | September 14, 1960 |
| Ravn Alaska | regional airline | Anchorage | January 1, 2010 |
| Rawlings | sporting goods manufacturer, business | Town and Country | 1887 |
| Razer Inc. | privately held company, business, public company | George Town, Singapore, Carlsbad, Irvine, San Francisco | 1998 |
| RC4WD | business | San Francisco | 2001 |
| RCA Records | record label, record company, business | New York City | 1901 |
| Re-Logic | enterprise | Floyds Knobs | 2011 |
| RE/MAX | brokerage firm, business, enterprise | Denver | 1973 |
| Real3D | business | Orlando | 1986 |
| Reality Kings | pornographic film studio | Miami Beach | 2000 |
| RealNetworks | privately held company, business, enterprise | Seattle | 1993 |
| Realty Income Corporation | real estate company, business, public company | San Diego | 1969 |
| Red Digital Cinema Camera Company | camera manufacturer, business, enterprise | Lake Forest | 2005 |
| Red Hat | business, enterprise, public company | Raleigh | March 27, 1993 |
| Red Robin | restaurant chain, public company | Greenwood Village | 1940 |
| Redback Networks | business | San Jose | 1996 |
| Redfin | real estate company, business, online real estate database | Seattle | 2004 |
| Reebok | business, enterprise | Boston | 1895 |
| Regency Enterprises | film production company | Los Angeles | 1982 |
| Regeneron Pharmaceuticals | business, public company | Eastview | 1988 |
| Regent Seven Seas Cruises | business | Miami | 1990 |
| Regnery Publishing | book publisher, publishing house | Washington, D.C. | 1947 |
| Remington Arms | business, enterprise | Madison | 1816 |
| Remote Control Productions | music publisher, business, enterprise | Santa Monica | 1989 |
| Renegade Kid | video game publisher, video game developer | Austin | 2007 |
| Republic Airways Holdings | business, public company | Indianapolis | 1973 |
| Republic Aviation Corporation | aerospace manufacturer | Farmingdale | 1931 |
| Republic Pictures | Poverty Row | Hollywood | 1935 |
| Respawn Entertainment | video game developer | Sherman Oaks, Los Angeles | 2010 |
| Revlon | business, enterprise, public company | New York City | 1932 |
| Revolution Studios | business | Los Angeles | 2000 |
| Rhino Entertainment Company | production company, record company, subsidiary company | Los Angeles | 1998 |
| Richard Childress Racing | auto racing team, business | — | 1969 |
| Rickenbacker | business, musical instrument manufacturing company | Santa Ana | 1931 |
| Rickenbacker | automobile manufacturer | Detroit | 1921 |
| Rio All-Suite Hotel and Casino | casino, hotel | — | January 15, 1990 |
| Riseup | internet service provider, mailbox provider, collective, worker cooperative, charitable organization | Seattle | 1999 |
| Rivian Automotive | business, enterprise, automobile manufacturer, public company | Detroit | June 2009 |
| Riviera Hotel and Casino | skyscraper, casino, hotel | — | 1955 |
| RJR Nabisco | business | Cobb County, Winston-Salem, New York City | April 25, 1986 |
| Rocket Lab | launch service provider, aerospace manufacturer | Long Beach | June 29, 2006 |
| Rockhurst University | private not-for-profit educational institution, university | Clayton | 1910 |
| Rockstar Games | video game publisher | New York City | December 1998 |
| Rockwell International | conglomerate, public company | United States | February 1973 |
| Rogers Locomotive and Machine Works | business | — | 1832 |
| Rogue | film production company | Universal City | 1997 |
| Rohm and Haas | business, enterprise | Philadelphia | September 1, 1909 |
| Roku, Inc. | business, enterprise, public company | Los Gatos | October 2002 |
| Roosevelt University | private not-for-profit educational institution, university | — | April 24, 1945 |
| Rooster Teeth | YouTube channel, film production company | Austin, Los Angeles, Flower Mound | April 1, 2003 |
| Ross Dress for Less | department store chain, enterprise, public company | Dublin | 1954 |
| Rotten Tomatoes | online film database, review site, business | San Francisco | August 19, 1998 |
| Rough Draft Studios | business, enterprise | Glendale | 1990 |
| Rowan University | public educational institution of the United States, public university | Glassboro | 1923 |
| Roxy Theatre | nightclub, music venue | — | September 23, 1973 |
| Royal Hawaiian Hotel | hotel, hotel building | — | 1927 |
| RSA | business, enterprise | Bedford | 1986 |
| RTX | defense contractor, business, public company | Arlington County | April 3, 2020 |
| Rutgers University Press | university press | New Brunswick | 1936 |
| Rutherford B. Hayes Presidential Center | library | — | 1912 |
| Ryan Aeronautical | business | San Diego | 1934 |
| Ryder | business, retail chain, public company | Coral Gables | 1933 |