Republican Heather Somers, a businesswoman and former Groton mayor and town councilor, soundly defeated Democrat Timothy Bowles Tuesday to win the 18th District state Senate seat in a rough-and-tumble campaign that focused more on vitriol than the issues.

With the win, Somers, 50, returned the sprawling eight-town district that stretches from the shoreline north to Plainfield to the GOP column, replacing five-term Democrat Andrew Maynard, who didn't seek re-election. Her win will help to balance the state Senate's make-up, with Somers reporting she had heard Democrats and Republicans will split the 36-member chamber 18-18 in the new legislative session.

Bowles, 66, a retired state employee and caretaker of his family farm in Preston, was drafted by his party to run after other possible contenders backed out. He is a former one-term representative and a former selectman in Preston.

Somers received 22,910 votes and Bowles 17,996 in an unofficial tally. Absentee ballots were not included.

On Tuesday evening, before the polls closed, Bowles and Somers stood in the dark outside the Pawcatuck Fire Department in Stonington, greeting voters at one of the district's busiest polling stations.

Although they stood just 10 or 12 feet apart, they didn't speak, not surprising, given the nastiness of the contest. By nearly all accounts, this race was probably the most bitter in the state.

Earlier in the day, while greeting voters at Fitch High School, Somers said she was "feeling hopefully optimistic" after so many people on their way into the polls across the district told her they were put off by Bowles' negative campaigning.

In Pawcatuck Tuesday evening, Bowles said both camps contributed to the mudslinging.

"It hasn't been a pleasant campaign to say the least," he said. "It's not my style."

And he added, "I have to take some responsibility, but it was both sides."

At the Somers' headquarters at The Spot in Groton where well-wishers gathered to see election results come in, Somers was declared the victor about 9:15 p.m., and a short while later, she received a call from Bowles congratulating her, and conceding.

In her very short speech to the crowd, Somers said given the contentiousness of the race, she had prepared a concession speech, to which those gathered roared, "Throw it away." She tore it up and dropped the scraps on a table.

She described her opposition as "great and vast" and said the campaign was filled with "terrible lies and mistruths and ludicrous accusations, but the truth as always does prevail."

Later, she said, "I can't guarantee any miracles for anyone, but I am ready to get to work for the state of Connecticut and I guarantee to you that tonight begins the recovery of Connecticut."

Statewide, Republicans eyed the 18th District, just one of two state Senate races without an incumbent on the ballot, as fertile ground for the GOP. Democrats have held a 21-15 edge over Republicans in the Connecticut Senate, but with the political turmoil nationally, and upheaval over spending and taxes in the state, Republicans strategized to capitalize and targeted about a half-dozen Senate races, including the Somers/Bowles contest. Somers, who was the GOP's lieutenant governor hopeful in 2014, was considered a strong candidate from the get-go.

While Bowles' campaign was laser-focused on Somers' involvement 15 years ago with a biotech manufacturing firm and made allegations that she cheated taxpayers for personal gain, the Connecticut Business and Industry Association enthusiastically supported her bid, selecting her race as one of four Senate contests that the association backed this year.

a.baldelli@theday.com