Individual Details

George Conn was first married to Eunice Cheney, 25 Jun 1823, Vigo Co IN (Indiana State Library Online - Indiana Marriages Through 1850).
Nelson, born 1823, was their son, not the son of Harriet Allen, because George did not marry Harriet until 1829.
October Term, 1825, Circuit Court, Vigo Co IN. John Britton vs. Harriet Britton. Petition for divorce. Granted. "It is ordered ...John Britten be and he is hereby divourced from the cares of Matrimoney With the said Harret Britton and it is further ordered adjudged and decreed that the said Harriet Britton be and she is hereby released from the cares of matrimoney With the said John Britton."

Although the date of Harriet's death has been passed down as 8 Jul 1845 - she was very much alive in the 1850 census. Perhaps she died in 1855...
FindAGrave has a picture of her marker, Woodlawn Cemetery, Terre Haute. She died July of 1855. She was interred 8 Jul 1855. Placed by the Wabash Valley Genealogy Society.

Birth	10 May 1803
Marriage	15 Sep 1819	Vigo County, Indiana - John Britton
Divorce	Oct 1825	Vigo County, Indiana - John Britton
Marriage	24 Dec 1829	George Conn
Death	Jul 1855	Terre Haute, Vigo County, Indiana

Spouse	George Conn (1793 - )
Child	Chloe Allen Conn (1831 - 1904)
Child	Adaline Conn (1838 - )

Spouse

John Britton (1792 - 1853)

Father	PETER BUELL ALLEN (1775 - 1833)
Mother	MARY PETERSON (1774 - 1832)
Sibling	Henry Cromwell Allen (1797 - 1837)
Sibling	Ira Allen (1799 - 1866)
Sibling	Catherine Allen (1801 - 1821)
Sibling	Myron Holley Allen (1805 - 1872)
Sibling	Amanda Allen (1807 - 1866)
Sibling	Chloe Ward Allen (1809 - 1869)
Sibling	PETER BUELL/BENTON ALLEN (1811 - 1901)
Sibling	Adaline Allen (1814 - 1857)