His next assignment sent him north to Vancouver Barracks in the Oregon Territory.[74]
Grant tried several business ventures but failed, and in one instance his business partner absconded with $800 of Grant's investment, equivalent to $21,000 in 2021.[75][76] Concerning local Indians, Grant assured Julia, by letter, they were harmless, and he developed empathy for their plight.[77] Grant witnessed white agents cheating Indians of their supplies, and the devastation of smallpox and measles, transferred by white settlers.[78]
Promoted to captain on August 5, 1853, Grant was assigned to command Company F, 4th Infantry, at the newly constructed Fort Humboldt in California.[79] Grant arrived at Fort Humboldt on January 5, 1854, commanded by Lieutenant Colonel Robert C. Buchanan, a martinet officer, with whom Grant had earlier crossed paths at Jefferson Barracks.[80] Separated from his wife and family, Grant began to drink.[81] Colonel Buchanan reprimanded Grant for one drinking episode and told Grant to "resign or reform."Grant told Buchanan he would "resign if I don't reform."[82] On Sunday, Grant was found influenced by alcohol, but not incapacitated, at his company's paytable.[83] Keeping his pledge to Buchanan, Grant resigned, effective July 31, 1854.