While the state's attorney general lost the election to Republican state Sen. Scott Brown 52 to 47 percent in unofficial statewide results, locals headed to the polls in surprisingly large numbers to back the Williams College graduate who was raised in North Adams.
Thirty-one of the county's 32 towns and cities went to Coakley, the margin of victory swinging dramatically in her favor: 29,849 votes to 13,294.
Only Otis went to Brown, 283 to 265.
Williamstown and North Adams proved to be among Coakley's strongest bases, as more than 77 percent of voters there supported her.
More than 45 percent of registered voters turned out in Pittsfield, where the numbers had Coakley besting Brown by better than a 2-to-1 margin (8,990 to 3,803).
Pittsfield City Clerk Linda M. Tyer was "surprised and really pleased" with the turnout, which soared past last month's primary election, when just 14.7 percent of city voters turned out.
Voter participation across the county ranged from 40 percent in Adams to 68 percent in Tyringham.
Many said the pending health care reform legislation and the all-out political blitz surrounding the election pushed them to the polls.
The special election drew national attention, as political experts viewed it as a referendum vote on President Barack Obama's first year in office and his proposed health care reform.
"We're the poster children for the health care issue," said Mary Beth Anello, who along with her husband, voted for Coakley.
Richard Anello is recovering from a broken right leg suffered in an October 2008 fall. Since then he's undergone six surgeries and the Pittsfield couple has spent thousands of dollars on medical bills.
But while many saw a vote for Coakley, 56, as a vote for health care reform, Brown supporters questioned the Democrats' rush to pass the sweeping legislation.
"I don't have much faith in Congress pushing through something so important in just a few months," said George Kastrinakis, of Lee, a Brown supporter.
Brown, 50, had promised to be the 41st vote in the U.S. Senate to shoot down the current health care reform package.
Several voters polled by The Eagle said they supported Coakley because of her local connection and to stay true to their party.
"Any opportunity to put a [former] Berkshire resident in the U.S. Senate, we should," said Christopher Farrell of Pittsfield.
However, Lisa Reilly, of Pittsfield, who backed Obama in 2008, voted for Brown to create a balance in Washington D.C.
"If Congress is mostly Democrats, no one will listen to the other side," Reilly said.
"I saw more positives in Brown," added daughter Caitlin Reilly, an Obama supporter who also voted republican on Tuesday.
Supporters of both parties from around the nation descended on the state to rally for their candidates. Local residents received pre-recorded phone messages from Obama, Vice President Joe Biden and former President Bill Clinton in the days leading up to the election. And Obama flew into Massachusetts Sunday to campaign for Coakley in an effort to give the Democratic candidate a last-minute push in the polls.
Many Berkshire voters agreed that the campaign seemed to get out of hand at its close and took on an air of negativity.
Lenox Town Clerk Marie Duby found many residents "agitated" by the political barrage. "One person said it was like an invasion of privacy," said Duby.
Paula De Laurentiis, of North Adams, said the issues of health care reform and a woman's right to choose spurred her to vote.
"Martha Coakley grew up in my neighborhood," she said. "I talked to neighbors who knew her so I would be sure of her values."
New England Newspapers reporter Meghan Foley contributed to this article.