History of Donner Pass | Told By the Always Accurate Wikipedia

The Donner Party (sometimes called the Donner-Reed Party) was a group of American pioneers led by George Donner and James F. Reed who set out for California in a wagon train in May 1846. They were delayed by a series of mishaps and mistakes, and spent the winter of 1846–47 snowbound in the Sierra Nevada. Some of the pioneers resorted to cannibalism to survive.

The journey west usually took between four and six months, but the Donner Party was slowed by following a new route called Hastings Cutoff, which crossed Utah's Wasatch Mountains and Great Salt Lake Desert. The rugged terrain and difficulties encountered while traveling along the Humboldt River in present-day Nevada resulted in the loss of many cattle and wagons and splits within the group.

By the beginning of November 1846, the settlers had reached the Sierra Nevada where they became trapped by an early, heavy snowfall near Truckee (now Donner) Lake, high in the mountains. Their food supplies ran extremely low and, in mid-December, some of the group set out on foot to obtain help. Rescuers from California attempted to reach the settlers, but the first relief party did not arrive until the middle of February 1847, almost four months after the wagon train became trapped. Of the 87 members of the party, 48 survived to reach California, many of them having eaten the dead for survival.

Historians have described the episode as one of the most bizarre and spectacular tragedies in Californian history and western-US migration