Individual Details

I have been unable to find any likely Harmon that could be this Hiram in either 1840 or 1850. The following deed in 1836 would suggest that Ruth was a widow by 1836 - a married female could not have been selling property.
One online database stated that Hiram died 1831 in the Black Hawk War. However, I have yet to find in his name in any listing of Indiana soldiers that served.

DB A, p.380
20 Feb 1827 James Harmon & Philadelphia his wife of Marion Co to Elizabeth Harmon, Charles and Hirum Harmon [Charles & Hiram his brothers, perhaps his mother Elizabeth]. $25. Tract: on South end of South half of the 80 acres of the NW quarter and west half of S14, T17, Range ___ East. Bounded begin middle stake between sections 14 & 15 on bank of Eagle Creek ….20 acres.
Signed: James Harmon, Philadelphia Harmon.
Presence of Jacob Sheets, Andrew Sheets.
Rec. 22 Feb 1837


Marion Co, DB H, p.147
5 May 1836 Alexus Jackson & Mary his wife and Ruth Harmon wife of Hiram Harmon of Marion Co to Charles Harmon. $220 paid by Charles. All that tract South end of NW quarter of S14, T17N, Range 2 E, containing 40 acres. In district of lands to be sold at Indianapolis land office. Signed: Alexus Jackson, Mary (x) Jackson, Ruth (x) Harmon
Wit: William Harmon Senr, James A. Carter
6 May 1735, Acknowledged by Alexus; Mary relinquished. Rec. 22 Apr 1837


Although Hiram's wife appears to be a woman capable of selling land (which could only be if he were dead or they had divorced), Hiram was alive in 1837 to sign and prove the deed disposing of some of his father's estate. Ruth is head of household in 1840 in Shelby, IL, where she marries twice more. Hiram's brother Charles was also living in Shelby Co in 1840 and had an extra adult male in his household, of an age to possible be Hiram.

Birth	1810
Marriage	1 May 1831	Marion County, Indiana - Ruth Parrish
Death

Spouse	Ruth Parrish (1813 - 1853)
Child	Mary Jane Harmon (1832 - 1856)
Child	Zerilda E. Harmon (1833 - )
Child	Mariah Emily Harmon (1835 - 1901)
Child	Adaline Harmon (1837 - 1894)

Father	JOHN L. HARMON (1767 - 1825)
Mother	ELIZABETH BYRD (1771 - 1869)
Sibling	William W. Harmon (1788 - 1866)
Sibling	Henry Harmon (1790 - 1826)
Sibling	Richard Harmon (1793 - 1860)
Sibling	John Bird Harmon (1795 - 1860)
Sibling	JAMES HARMON (1797 - 1847)
Sibling	Nancy Jane Harmon (1799 - 1872)
Sibling	Mildred\Emeline Harmon (1801 - 1838)
Sibling	Sarah Harmon (1803 - )
Sibling	Mary Harmon (1805 - 1880)
Sibling	Elizabeth Harmon ( - )
Sibling	Charles Harmon (1811 - 1883)