Samuel bought land in Greene County, Tennessee in 1817 from his mother-in-law, Isabella Carmichael, and sold it in 1833. He was in the census there in 1830. He acted on behalf of his brother Joseph Duncan in the Greene County, Tennessee Chancery Court action by the heirs of Uriah Hunt in 1928. He was in Monroe County, Tennessee in 1833 and 1835.

Samuel and Elizabeth's home was built on the dividing line between Washington and Greene County, Tennessee. Elizabeth (Carmichael) Duncan died 6 August 1839 and Samuel Duncan died a little over a month later on 19 September 1839 from an epidemic of typhoid fever.

Will of Samuel Duncan
Monroe Co. TN Wills, Vol.1, 1833-1860, and Vol. A

1-39/40: 19 Sept. 1839, Samuel Duncan of Monroe Co. TN, weak of body; to Andrew J. Duncan, George B. Duncan, Archibald W. Duncan and William A. Duncan (my sons) all my real and personal estate to be divided equally as soon as William A. Duncan becomes of age except so much as may be hereinafter mentioned; to my sons John C. Duncan and James K. Duncan also my daughter Issabella Johnston formerly Issabella Duncan and Sarah Duncan $350 each to be paid out of the proceeds of my estate by the said Andrew J. Duncan, George B. Duncan, Archibald W. Duncan and William A. Duncan in the following manner, viz, in March 1844 1/3 paid to each, in March 1845 1/3 and in March 1846 the balance or remaining thirds. To my son Archibald W. one bay horse; to my daughter Sarah one horse and saddle, the horse to be equal in value to the one above described to be paid over by the said Andrew J. Duncan, George B. Duncan, etc. as soon as she comes of age or may need the services of the said horse; to my son William one horse of the above description paid over as soon as he may arrive to the age of 21 also one saddle; to my daughter Sarah three beds and furniture; to my son George B. Duncan one bed etc.; to my son Archibald W. Duncan one bed etc.; to my son William A. Duncan one bed etc.; to my son Andrew J. Duncan all my household and kitchen furniture except so much as is above otherwise appropriated; so much of my personal property be sold as will be sufficient to satisfy my outstanding debts; appoint friends John Duncan Sen., Robert Russell and Andrew J. Duncan executors. Wit. Josiah Rowan, John E. Grigsby. No recording or probate date given.
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His sons John Carmichael and James Kennedy are in Monroe County in the 1840 U.S. census. At this time the slave question was of great interest. The Duncan's had never been slave holders and not desiring to live and raise their families among slave holders all the children but one came to Iowa. George Bell Duncan and James Kennedy Duncan and their families came to Louisa County in 1845 and Andrew Jackson and William Alexander and their families, two years later, in 1847. By 1851 all the children but Keziah had come to Iowa.

Sources: Some Duncan Families of Eastern Tennessee Before 1800; page 39;
The Duncan Family, page 4;
History of Louisa County, Iowa, pages 551-552