In the spring of 1846, a group of nearly 90 emigrants left Springfield, Illinois, and headed west. Led by brothers Jacob and George Donner, the group attempted to take a new and supposedly shorter route to California. They soon encountered rough terrain and numerous delays, and they eventually became trapped by heavy snowfall high in the Sierra Nevada Mountains. Purportedly reduced to cannibalism to survive through the winter, only half of the original group reached California the following year. Their story quickly spread, and before long the term “Donner Party” became synonymous with one of humanity’s most ingrained taboos.

The Donner party left Springfield, Illinois, in April 1846. Led by two wealthy brothers, Jacob and George Donner, the emigrants initially followed the regular California Trail westward to Fort Bridger, Wyoming. From there, however, the emigrants decided to leave the established trail and take a new and supposedly shorter route to California laid out by an unscrupulous trail guide named Lansford Hastings. Hastings was not at Fort Bridger at the time—he was leading an earlier wagon train along his new route. He left word for the Donner party to follow, promising that he would mark the trail for them.

Reassured, the group of 89 emigrants left Fort Bridger with their 20 wagons and headed for Weber Canyon, where Hastings claimed there was an easy passage through the rugged Wasatch Mountains. When they reached the head of the canyon, they found a note from Hastings attached to a forked stick. Hastings warned the Donner party that the route ahead was more difficult than he had thought. He asked the emigrants to make camp there and wait until he could return to show them a better way.

Hastings’ note troubled the emigrants. To return to Fort Bridger to pick up the established route would have meant wasting several days. They decided to wait for Hastings. After eight days, when Hastings had still not arrived, the emigrants sent a messenger up the canyon to find the guide. The messenger returned several days later with instructions from Hastings to follow another trail, and the emigrants complied. The alternate route, however, turned out to be even worse than the Weber Canyon road, and the emigrants had to carve a fresh road through thick trees and boulder-strewn ground.

The Donner party finally made it through the Wasatch Mountains and arrived at the Great Salt Lake. Hastings’ route had cost them 18 valuable days. Unfortunately, their difficulties were only beginning. The “shortcut” to California had cost them many wasted days, and the Donner party crossed the Sierra Nevada Mountains late in the season. On October 28, a heavy snowfall blocked the high mountain passes, trapping the emigrants in a frozen wilderness. Eventually reduced to cannibalism to survive—at least according to legend—only 45 of the original 89 emigrants reached California the following year.