Another account claims Farnham left with Hunt on the "Pedler" and was dropped off on the coast of Kamchatka on April 3, 1814 and, after arriving in St. Petersburg, instead left from Hamburg, Germany, whereupon he arrived to meet Astor in New York. Employed by Astor to oversee the business interests of American Fur Company in the Great Lakes region, he was arrested by the British as a spy during the War of 1812. Transported for trial to Prairie du Chien, several of his friends appealed to British authorities of his innocence and the charges were eventually dropped. He made one of the first trips into the Midwest United States on behalf of the American Fur Company in 1817, and later formed a partnership with George Davenport trading with the Sauk and Fox in the Missouri Valley. During this time he took a wife from the Menominee tribe named Agathe Wood and had a daughter. Moving to St. Louis in 1826, he married a white woman Susan Bosseron, the daughter of Charles Bosseron. That same year, while trading at Fort Armstrong, he and Davenport founded a settlement along the Mississippi River known as Stephenson. Along with the town of Farnhamsburg, the two settlements would eventually become the site of Rock Island, Illinois. He also founded Muscatine, Iowa, after leaving the Rock Island area some years later. He and Ramsey Crooks absorbed the Columbia Fur Company in 1827 and, with former Columbia traders such as Kenneth MacKenzie, the two founded the American Fur Company's "Upper Missouri Outfit". He remained in charge of the rival trading post near Fort Edwards (itself near Fort Johnson) and, in 1829, he founded another trading post several miles upriver at present-day Keokuk, Iowa which was run by Mark Aldrich. He died of cholera in St. Louis on October 23, 1832. He reportedly survived "only two hours after having been attacked with that then new and fatal disease". His wife and child died of consumption a few years later. His close friend and former trading partner Ramsey Crooks wrote in a letter to Pierre Chouteau, Jr. regarding news of his death.