Jacob Butler Varnum (1788-1874) was born in Dracut, Massachusetts, to Mary Butler and Joseph Bradley Varnum (c.1751-1821), senator from Massachusetts. Between 1811 and 1812, Varnum served as a factor (trade agent) at the United States Indian trading post at Sandusky, Ohio. After the outbreak of the War of 1812, Varnum returned east, and was appointed captain of the 40th Massachusetts regiment (1813-1814). Captain Bradley appointed Varnum as Matthew Irwin's replacement as factor for the Chicago Trading House in the North Western Territory, an office he held from 1816 to 1822. While in Chicago, Varnum witnessed the 1821 Treaty of Chicago signed by Lewis Cass and Solomon Sibley representing the United States, and the Ottawa, Ojibwe, and Pottawattamie tribes. In 1816, Varnum married Mary Ann Aiken of Detroit. She died during childbirth in 1817, while living with her husband in Chicago. Next he married Detroit native Catherine Dodemead (b.1800) in 1819. Varnum left government service in 1822, and moved to Washington D.C. where he made a living as a merchant. By 1833, he and his wife had moved to Petersburg, Virginia. At the time of his death in 1874, only his son, George W. Varnum, survived him.