The winner, Julie Leach, 50, said she was still in "disbelief" -- adding that she told her boss that she doesn't need a raise before quitting her job at a fiberglass company.
"I don't know what to say. I'm just overwhelmed," she said during a news conference this morning.
Leach described the day she discovered she was the winner.
"I was having a really bad night at work and I thought I better check my numbers," she said, adding that she was "shaking" when she slowly realized she won. She said she went back to work, where she is a supervisor, to ask her co-workers to verify the numbers.
She said she's accepting the lump sum cash option of $197.4 million. After taxes, her payout will be $140 million. She added, "I didn’t go to sleep for over 30 hours when I found out."
When asked if she will continue working, Leach said, "I quit automatically. I was done." She said it was a "nasty, dirty job" that she had for more than 20 years.
She said that after she told her boyfriend of 36 years, Vaughn Avery, "He wanted to go to work. I said, 'Are you crazy? We don't have to work anymore.'"
She said she wants to take care of their children and 11 grandchildren. Though he has tried proposing to her "several" times in the past, she has refused, pointing to their friends who have gotten divorced.
"I said he would have to sign a pre-nup now," she said with a laugh.
She said she hopes to buy property in Michigan for the whole family.
"I’m going to take care of my kids," she said. "I don’t want them to work the way I had to work and deal with the things I had to deal with in life. I want to make it a good life for them and take care of them."
When asked what her grandchildren have said about the news, Leach said, "'Grandma's rich.' I heard that one."
The ticket was sold at a Shell gas station in Three Rivers, Michigan, just a drive away from the border with Indiana. The drawing took place on Sept. 30
The winning numbers were 21, 39, 40, 55, 59 and Powerball 17.
The state's largest Powerball jackpot ever was $337 million, which was won by Donald Lawson on Aug. 15, 2002.