Experts say people in that age group developed their left-leaning political values during the Depression era of their youth, ABC News reported Monday.
The U.S. Census Bureau says there are approximately 53,000 Americans 100 years old or older.
Mitt Romney, the Republican presidential nominee, is favored by voters 65 and older, polls indicate. That group grew up politically during the administrations of Dwight Eisenhower and Harry Truman.
There is no precise data on centenarian voting patterns. However, data from the Pew Research Center coupled with interviews of people 100 or older suggest the group remains more progressive than slightly younger Americans.
"One way to look at the political leanings of generations is to sort people by the political environment when they became politically engaged," says Pew in a report that analyzes generational voting during this election campaign.
A web video by the Obama campaign features a 106-year-old Kentucky woman to promote the support it has from centenarians.
Pew forecasts the political inclinations of the nation's oldest voters will shift more to the right as those 65 and older become the next centenarians.