| Public Library of Science | nonprofit organization, website, open-access publisher, academic publisher | Levi's Plaza | July 11, 2001 |
| Pulse | LGBT historic place, LGBTQ nightclub | — | 2004 |
| Punahou School | university-preparatory school | Honolulu | 1841 |
| Purdue Pharma | pharmaceutical company | Stamford | 1892 |
| Quaker Oats Company | business, enterprise | Chicago | 1877 |
| Qualcomm | business, public company | San Diego | July 1985 |
| Qualtrics | business, public company | Provo | 2002 |
| Queens College | public educational institution of the United States, university | — | 1937 |
| Quest Software | business | Aliso Viejo | 1987 |
| Quiznos | fast food restaurant chain, restaurant chain | Denver | 1981 |
| QVC | television station, business, specialty channel | Düsseldorf | 1986 |
| 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 |