Mary Janet Willoughby (maiden name: Gates) was born around 1820 in New York to Joseph Gates. The family eventually moved to Madison County, Illinois, and she married James Goforth Willoughby on July 30, 1840. They had at least four children: McDonough, born on May 22, 1841; Celestia, born around 1843; James, born around 1850; and Adelaide, born around 1857. They lived in St. Clair County, Illinois, and her husband worked as a farmer. By 1850, they owned $1,800 of real estate. They eventually returned to Collinsville, and by 1870, they owned $10,000 of real estate and $500 of personal property. She died in 1873.