Marion Peck, later Mrs Farquhar, was the daughter of Harold S. and Annie Peck. At the time of the 1880 census they were living in Chicago, Marion (then 8) and two sisters, Amanda (aged 5) Haroldine (aged 1).
JW met Mrs Peck and was commissioned to paint a portrait of her daughter in 1895 (see the original portrait commission, L. C. Kellogg to JW, 12 March , #02424). She was posing for Portrait of Miss Marion Peck (YMSM 439) from March 1895 at intervals for several years.
US census 1880 at http://www.familysearch.org (accessed 2005).