The feline adventure started in Portland, Ore., when the cat's owner, Ron Buss, let her out of the house on Sept. 1. The cat, white with patches of dark gray, usually left for no more than a couple of hours at a time, but this time she didn't return.
When Michael King, who has been homeless since 2003, spotted Mata Hairi, she was crouched under a table at a cafe, trying to stay out of the pouring rain.
"I see cats all the time," King said. "I don't pick up cats. I don't want a cat, especially a full-grown one.
And he definitely didn't want to haul around the needed food and bowls that would add 20 pounds to his pack.
"Something told me to grab her. I don't know," King told the Independent Record (http://bit.ly/17T7QRQ ).
He named the cat Tabor, for the cafe where he found her.
She traveled with King as he hitchhiked to California, back to Portland and out to Montana, where King's foster father lives.
People often stopped them and asked to take photos.
"She's a hit on the streets of Portland," King said. "Very rarely do you see a cat riding on the top of someone's backpack."
King and his foster father, Walter Ebert, recently took the cat to a veterinarian in Helena, where a scan found a microchip, and the vet was able to contact Buss.
Buss is planning a party marking Mata's return, and King agrees it's an occasion for celebration.
But it's going to be emotional for King, too.
"I didn't want a cat in the first place. I just thought I was saving someone's cat," King said. "And that's what I've done. Now I've grown attached to her.
"My pack will be 20 pounds lighter," he said, "but a big hole, a big hole."
Information from: Independent Record, http://www.helenair.com