Emigrants thought the deserts of Utah and Nevada were difficult. Animals died. People died. Goods, wagons, and animals had to be abandoned. After successfully crossing those deserts, pioneers believed they were through the worst of the journey.
Then they saw the immense Sierra, the most difficult obstacle on the path to California—to their new lives and opportunity. The first wagon train to reach California with wagons was the Stephens Murphy Townsend Party in 1844. They arrived late in the season and hurried to get over the pass, leaving half of their wagons at Donner Lake.
When the party got to Big Bend by the Yuba River, just west of the summit, the men left the women in children to get help in California. The Stephens Party had to take apart their wagons to get them up Donner Pass. It was an immense feat.
Emigrants who followed in 1845 and early in 1846 had to do the same. But later in 1846, Roller Pass was discovered just two miles to the south. There the wagons could be pulled up without taking them apart.
To do that however, all of the oxen had to be linked at the top of the pass with chains, ropes, and occasionally tree branches in order to pull each wagon up. Later in 1846, Coldstream Pass, between Donner and Roller Passes, was discovered and it became the main route for emigrants crossing Donner Pass into California.
The emigrants who crossed Donner Pass were among those to form California. Today a visit to Big Bend will bring you to slabs of granite still showing the rust marks of thousands of iron wheels from emigrant wagons.