Douglas Preston in The New York Times:
Certain stories in American history carry archetypal power, and the dark majesty of the Donner catastrophe is one of them. In the winter of 1847, when the first skeletonized survivors stumbled out of the Sierra Nevada, the Donner story seized the American imagination and has never let go, generating a vast but unreliable historical record burdened with exaggeration, lies, melodrama and prurient disgust. Cannibalism was the prime reason the story lodged itself in our national psyche; but more than that, the fate of the Donner party was a denial, a violent repudiation, of the myth of Manifest Destiny: Here were a group of westward pioneers, the very picture of courage, resourcefulness and pluck, who ended up reduced to a level of squalor and barbarism almost beyond words.
The saga began in April 1846 when a prosperous band of emigrants left Springfield, Ill., heading for new lives in Alta California, then part of Mexico. At the Little Sandy River in Wyoming, 87 souls under the leadership of George Donner made a fateful decision: to follow the Hastings Cutoff, a new shortcut championed by a mountebank named Lansford Hastings. The cutoff routed them southward of the established trail, through the Wasatch Mountains and the Great Salt Lake Desert, where they were forced to build a road, suffered terribly from thirst and lost many oxen. Discipline broke down: One man was murdered for his gold; another had killed in self-defense and was banished; and a third, unable to walk, was left behind to die. By the time the emigrants reached the foothills of the Sierra in late October, they were fatally behind schedule, demoralized and already starving. Not far from the pass, an apocalyptic blizzard descended on them. The next morning, Keseberg wrote, “All I could see was snow everywhere. I shouted at the top of my voice. Suddenly, here and there, all about me, heads popped up through the snow. The scene was not unlike what one might imagine at the resurrection, when people rise up out of the earth.” But it was anything but a resurrection. Fifty-nine people in the vanguard were forced to take refuge near Truckee Lake (now Donner Lake), while the rest of the party, consisting of 22, was snowbound in a meadow six miles back. There most of them remained for months, as storm after storm piled up about 20 feet of snow, burying their rough cabins, lean-tos and crude shelters. In these filthy hovels they starved and began to die and eventually ate the dead — cooking flesh and organs, cracking bones for marrow, boiling them for grease, and processing them down into nubbins.
More here.