Kenneth Allen and his wife Kristy found the bank bag with $12,764.73 and a man's wallet Saturday evening, officer Jim Knoll, a spokesman for the Clarksville police, said in a release.
Kenneth told the Clarksville Leaf-Chronicle he never thought to keep the money "because that's not the right thing to do."
"I knew I had to return it," he said. "Someone might have needed that for something really important."
The Allens tried to track down the owner, but after no success, turned the investigation over to Clarksville police. Officers found the owner, a 51-year-old man who had suffered a reaction to medication and was hospitalized. That's why the bag was left behind, Knoll said.
Kenneth said the owner, whose name was not reported, has since called to express his thanks for the return of the money.
"If anyone else had found this money, they'd have thrown one heck of a party," he said. "We were meant to find it."