By Kevin Murphy

(Reuters) - For 46 years, a canoe thought to date to the 1700s sat in the back of a display case as a minor exhibit at a small museum run by a volunteer historical group in Minnesota.

But this week, archaeologists who conducted radio carbon tests on the canoe said it was crafted almost 1,000 years ago, making it the oldest canoe in the state and shedding light on early navigation of Minnesota lakes.

"It was a total shock," said Russ Ferrin, president of the Western Hennepin County Pioneer Association museum. "It's been kind of in a background display; not much was made of it."

The association got the canoe in 1960 and placed it in the museum starting in 1968, Ferrin said.

The dugout canoe was hollowed out of a single large tree, said Ann Merriman, nautical archaeologist for Maritime Heritage Minnesota, which researched the age of the canoe and seven others as part of a Maritime History Minnesota project.

Indians made dugout canoes by first burning out the center of a felled tree trunk and then carving the inside, she said.

The canoe was found in 1934 buried in mud in Lake Minnetonka, a large body of water in suburban Minneapolis, by a family building a dock, Ferrin said.

It passed through various museums until the pioneer association acquired it and later put it on display at an old schoolhouse converted to a museum, Ferrin said. The museum is only open Saturdays and by appointment.

Merriman said she had seen a picture of the canoe but did not know where it was until she went looking for more at the museum.

"We were looking for that canoe and there it was," Merriman said.

Archaeologists estimated the canoe was made between 1025 and 1165. Dugout canoes as old as 5,000 years have been found in the southeastern United States, but the Minnesota canoe may be the most significant nautical find in the state's history because of how well it was crafted and preserved, Merriman said.

No longer a background piece, the canoe has been moved to a prominent spot in the museum. It is also coveted by at least one major Minnesota museum, Ferrin said.

"We intend to keep it as long as we can protect it," he said.

(Reporting by Kevin Murphy; Editing by David Bailey and Richard Chang)