James left New Jersey in 1834 and headed west. After spending time in Indiana and Illinois, he settled in Missouri (in an area created by the Platte Purchase) in 1844, and began farming along the Missouri River. It was there that he contracted malaria, a common affliction in the area. On the advice of his doctor, Marshall left Missouri in the hopes of improving his health. He joined an emigrant train heading west and arrived in Oregon's Willamette Valley in the spring of 1845. He left Oregon in June 1845 and headed south along the Siskiyou Trail into California, eventually reaching Sutter's Fort, California, an agricultural settlement, in mid-July. John Sutter, the founder of Sutter's Fort, was also the "alcalde" of the area, as California was still a Mexican possession in 1845. Sutter hired Marshall to assist with work at the sawmill, and around the fort (carpentry, primarily). He also helped Marshall to buy two leagues of land on the north side of Butte Creek (a tributary of the Sacramento River) and provided him with cattle. It was here that Marshall began his second stint as a farmer.