The 1850 census for Meigs County - Sarah is now married to John Stewart.
Ohio, Meigs Co., Olive TWP 1850 # 375-384

271 02 375 384 Stewart John S. 58 M farmer Md - - - -
271 03 375 384 Stewart Sarah 49 F Pa - - - -
271 04 375 384 Ollum Isaac 15 M farmer Ohio - X - -
271 05 375 384 Ollum Menerva 13 F Ohio - X - -

271 06 376 385 Harrison Lewis M. 27 M farmer Ohio - - - -
271 07 376 385 Harrison Martha 21 F Ohio - - - - [<-----Martha Ollum?]
271 08 376 385 Harrison Sarah E. 3 F Ohio - - - -
271 09 376 385 Harrison Emma J. 1 F Ohio - - - -
271 10 376 385 Harrison Mary I. 2 mon F Ohio - - - -

They, Lewis and Martha, have been married since 25 Jul 1845
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1860 U.S. Census of Adel Twp., Dallas Co., IA page 609
625, 627, Lewis M. Harrison, 37, Carpenter, 300, 300, Ohio
Martha, 31, OH
Elizabeth L., 14, OH
[next page]
626, 628, Emma J., Harrison, 11, OH
Mary V., 9, OH
Minerva A., 8, OH
Charles D., 5, IA
Wesley M., 3, IA
William H., 4/12, IA

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Unable to locate Lewis in the Ancestry.com index for 1870 in Adel.

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From, I believe, Paul Van Wey’s Ultimate Family Tree website:
http://www.uftree.com/UFT/WebPages/Paul_Van_Wey/VANWEY/d0/i0000260.htm#i260

HARRISON Family
First Generation
1. Lewis M.1 Harrison was born in Ohio Abt 1823.
He married Martha Ollum. Martha was born in Ohio Abt. 1829.
Lewis M. Harrison and Martha Ollum had the following children:

2 i. Ike W.2 Harrison.
3 ii. Oran H. Harrison.
4 iii. Minerva A. Harrison. She married Overton.
5 iv. Wesley Harrison.
6 v. Sarah Elizabeth Harrison was born in Ohio Abt. 1847. She married Bilderback.
7 vi. Emma Jane Harrison was born in Ohio Abt. 1849. She married Thomas Benson 29 March 1865.
8 vii. Mary Virgina Harrison was born in Olive Twp, Beigs County Ohio May 25, 1851. Mary died June 3, 1923 in Angola, Labette County Kansas, at 72 years of age. She married John Denton Young in Independence, Montgomery County Kansas, December 29, 1875. John was born in Vinland, Winnebago County Wisconsin May 30, 1852. He was the son of Phillip Atherton Young and Mary Eliza Rowland. John died December 9, 1930 in Angola, Labette County Kansas, at 78 years of age. (See John Denton Young for the continuation of this line.)