Closs, 13, was discovered by the Douglas County Sheriff's Department, the Barron County Sheriff's Department, which led the search for Closs, wrote on Facebook Thursday.
Sheriff Fitzgerald says she will be reunited with relatives later tonight.
CBS Minnesota spoke to Jayme's aunt Sue on Thursday evening, who said her niece was now in the hospital.
"Shortly after this [finding Jayme] a suspect was taken into custody in regards to this case", the statement said.
On Thursday evening the Barron County Sheriff's Department was notified by the Douglas CO WI Sheriff's Department that they had located Jayme Closs alive.
According to ABC News, Jayme was kidnapped after her parents were found murdered in their Wisconsin home in October. WDIO-TV plans to carry the news conference live at about 10 a.m. I can't wait to get my arms around her. "I've always been a glass half-full kind of guy", Fitzgerald said at the time.More news: Michael Cohen Agrees to Spill the Beans in Public Congressional Testimony
More news: US, China wrap up talks on tariff battle
More news: US Special Representative Zalmay Khalilzad On Afghanistan To Visit India
Authorities didn't release any other details on where she was found.
"There was a lot of discouragement because this took quite a while to play out", Fladten said.
Detectives have pursued thousands of tips, watched dozens of surveillance videos and spent countless hours searching for Closs in the months since her disappearance, but their efforts have not yielded a suspect or suspects. It's just a great result we got tonight.
"I hope that she's in good shape", the mayor said. "It's unbelievable. It's like taking a big black cloud in the sky and getting rid of it and the sun comes out again".
"They were just two peas in a pod", family friend Melissa Salmonson tells PEOPLE, describing the pair as "almost inseparable" and saying Denise "was pretty quiet and shy like Jayme - they were similar". "She's just so shy". "I thought today was going to be the day, and then I find out two hours later she's found and I just can not believe this".
An ongoing criminal investigation is underway at a location in Walworth County.