A statement released by his family said Oberstar died in his sleep. A cause of death was not provided. His former chief of staff, Bill Richard, said Oberstar died at his home in Potomac, Maryland.
Richard said Oberstar was not ill and his passing came as a surprise. Oberstar's family said it was heartbroken.
"Jim was a loving husband, father, grandfather, friend and brother," the statement said. "While we mourn the loss of a good man, we also celebrate his life and his service. We ask for your thoughts and prayers, and understanding, at this very difficult time."
Oberstar, a Democrat, was elected to Congress in 1974 and served 18 terms before he narrowly lost to GOP challenger Chip Cravaack in 2010 as part of a
Republican takeover of the House. He was the state's longest-serving member of Congress, and became chairman of the House Transportation and Infrastructure Committee in 2006.
After he lost to Cravaack, Oberstar said he had loved serving northeastern Minnesota; his district included Duluth and the Iron Range.
"I can't change and wouldn't change any of the votes I cast this year to bring us out of this worst recession, chart a course for the future, to lay a foundation for a
better America, a better quality of life, a better quality of health care, rein in financial institutions, to give everybody equal opportunity and a better quality of life," he said after his 2012 loss. "I wouldn't change any one of those things."
Oberstar was the son of an underground miner from Chisholm. The family statement says he was grounded in the hard work, community and family loyalty of the Iron Range region.
"He was active and vivacious and went to one of the grandchildren's plays the night before," Richard said Saturday. "He was going to do more things with the grandchildren today. ... It's a surprise to everyone. I had lunch with him last week and he was in great shape, and alert and physically fit."
Oberstar is survived by his wife, Jean, four children and eight grandchildren.
Associated Press writer Brian Bakst in St. Paul contributed to this report.
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