Age: ?
Fourth Relief

         A mountain man and a mountain of a man, William Fallon or O’Fallon was known as “Le Gros” because of his huge size. He was “as spry as a cat,” a noted horseman who could mount a horse on the run or pick a coin from the ground as he galloped by. Fallon was active in many parts of the West from the 1820s into the 1840s. The landmark O’Fallons Bluff on the Platte is sometimes said to have been named for him.
       In June 1846 Fallon participated in the Bear Flag Revolt in Sonoma, recruited men for the California Battalion in October, and went south with them. By the spring of 1847 he was back in northern California and assumed the leadership of the Fourth Relief. His account of the expedition was published in the California Star on June 5, 1847. The late Joseph A. King dismissed Fallon’s report as a fraud, but despite its animosity towards Louis Keseberg, Keseberg himself confirms much of what Fallon says.
         In 1847 Fallon was among the companions of Gen. Stephen Watts Kearney, who was returning east. The next year, on his way back to California, Fallon and a single companion set out from Fort Hall. Their mutilated bodies were found alongside the trail some weeks later.    

Sources:

New Light on the Donner Party, Kristin Johnson

Ordeal By Hunger, George Stewart