Archaeologists have found the strongest evidence yet that the 1846 Donner Party — trapped in the Sierra Nevada by early blizzards and ultimately forced to eat some of their companions — made their winter camp at Alder Creek on the outskirts of modern Truckee, Calif.

Although parts of the site have been excavated before, the team found what appears to be the camp’s hearth, a key piece of evidence, as well as Donner-era artifacts and what may be a human bone scarred by the butcher marks of an ax.

If the bone is human, “that would really be the smoking gun” — the first physical evidence that the Donner Party resorted to cannibalism to survive the harsh winter, said team leader Julie Schablitsky, an archeologist who now works for the Oregon Department of Transportation.

It also provides strong support for the idea that the Alder Creek site is the actual winter camp. Although many descendants of the Donner Party view it as such, some historians claim the actual camp site is now submerged under the nearby Prosser Reservoir, and thus lost to history.

“We’re really thrilled about the discovery and hope this will trigger some funding so they can do more research,” said Frankye Craig, an amateur historian in Reno, Nev. “Everyone is hoping that they will turn up a diary or a buried box or something like that with items of interest to the Donner Party. There was no one left to carry that stuff out.”

The story of the Donner Party has gripped the imagination like few other tales of westward migration. George and Jacob Donner and James Frazier Reed gathered their families in the spring of 1846 and left Illinois for California.

On July 20, their group — 20 wagons and 81 people — made a fateful decision, departing from the well-known and frequently traveled wagon trail to take a “short cut” that promised to trim several hundred miles from their trip.

Ultimately, they were halted by a blizzard just short of what is now called Donner Pass and forced to erect a winter camp. By the time rescuers reached the party from Sutter’s Fort, half the party had died.

Many aspects of their struggle to survive are not completely clear.

Schablitsky and her colleague, Kelly Dixon of the University of Montana, discovered a hearth — fire-glazed rocks, charcoal fragments, burned bones and other objects. “That in itself is quite significant,” Hardesty said, because it indicates the presence of a campsite of the right age.

The team also found a section of a mammalian bone, possibly human, with ax marks on it, suggesting butchering.