HOULTON, Maine — No one wants to be at the Aroostook County Jail more than Libby.

She happily prowls the hallways and jail confinement areas in search of activity.

She loves to go out in the exercise yard.

And the staffers go out of their way to please her with treats.

All this, for a 7-year-old yellow lab-husky mix who has spent the past six weeks making both inmates and staff smile.

Local jail administrators were aware of dogs being used in prisons around the country and had been considering a dog for the facility for about a year.

Aroostook County Sheriff Darrell Crandall said Thursday that he thought a dog would reduce stress and teach prisoners valuable lessons, such as having to care for something other than themselves. They needed to work to find the right kind of dog to fit in at the jail and live with the residents, and the Central Aroostook Humane Society in Presque Isle helped provide the answer — at no cost.

And while the dog is good for the inmates, the inmates are good for the dog.

Betsy Hallett, executive director at the society, said Thursday that Libby had been brought to the animal shelter twice. She was adopted out after the first visit but then brought back again after the new family left her out on a chain and she tore the woodwork up on their door trying to get in while they were gone.

“It was evident she would do better with someone who would be there with her all day and preferably didn’t have kids,” said Hallett. “She was getting very depressed here. This was just perfect timing for them to call, this was the perfect fit for her. I went down to the jail for a visit recently and she was just as proud. She had her tail up in the air again and was walking around like she owned the place. It was great to see.”

Crandall said that Libby and her kennel are cared for by an inmate who has earned trustee privileges and who takes the dog places inside the facility while he does chores. The trustee, who asked not to be named, said last week that he enjoys having Libby tag along with him.

“She stays right with me and visits the other inmates at the same time,” he said. “They all really enjoy seeing her. She brings a smile to everyone’s face.”

Libby has some toys and a kennel that remain in the quarters with the trustee.

“Once in awhile we have to chase her off our beds,” he said, laughing.

Corrections Sgt. Shanna Morrison said that each of the inmates gets to spend 10 to 15 minutes a day with the animal. Libby has responded well to all of them, and they to her, she said.

“The first few times I talked to them about it,” she said. “I heard a lot of stories about the dogs that they had on the outside.”

Crandall said he is happy with the results he is seeing.

“Dogs are very non-judgmental,” he said. “They can make anyone feel good about themselves. Everyone needs that.”