Ted Kennedy was a U.S. senator.
The Chappaquiddick incident was a single-vehicle car accident on Chappaquiddick Island , Massachusetts on July 18 , 1969 that was the result of U.S. Senator Ted Kennedy 's negligence and resulted in the death of his 28-year-old companion , Mary Jo Kopechne , who was trapped inside the vehicle . Kennedy Compound . Their youngest son , Senator Ted Kennedy , lived in his parents ' house , and it was his main residence from 1982 to 2009 . Ted Kennedy . A member of the Democratic Party , he was the second most senior member of the Senate when he died and was the fourth-longest-serving senator in United States history , having served there for almost 47 years . He died on August 25 , 2009 , at his Hyannis Port , Massachusetts home . The United States Senate election of 1964 in Massachusetts was held on November 3 , 1964 with the incumbent Democratic Senator Ted Kennedy defeating his challengers .