The earliest known use of tobacco in the USA was by the Indians. The indians believed that tobacco was a healer of all things. Later when America was involved in the revolutionary war Tobacco was used as collateral for the loans that would help fund that war. As early as 1836 it was stated by New Englander Samuel Green that tobacco was actually poisonous, and could be deadly. In 1847 the famous Cigarette company Philip Morris is founded. Nearly a hundred years later iconic cartoon versions of Lucy and Ricky from "I Love Lucy" smoke Philip Morris Cigarettes in the original opening credits of their world famous television show. By the 1960's many health risks associated with smoking cigarettes began to be widely reported, by 1971 cigarette ads are no longer allowed on television in the U.S. By 1982 smoking is largely restricted in public areas, especially work environments, after it is discovered that lung cancer can be caused by second hand smoke. Also in 1982 lung cancer becomes the biggest killer in women before breast cancer. Today cigarette smoking is still the leading cause of preventable death in our country. In 2012 an estimated 43 million adults are still regular cigarette smoking. 

Sources: 

http://www.stopsmokingbible.com/how-many-people-in-america-smoke-cigarettes

http://archive.tobacco.org/resources/history/Tobacco_History20-2.html

http://academic.udayton.edu/health/syllabi/tobacco/history.htm