Your William Henry Thrasher is the son of Michael Thrasher and Margaret D. Barnet. Michael Thrasher is the brother of my ggggrandfather George Thrasher. They are the sons of Peter Thrasher. Michael was born 18 March 1807 in Wythe Co., Va. Michael and Margaret were married 21 sept 1829 in Wythe Co., Va. If you subscribe to Ancestry.com census you will find William H. Thrasher in Van Buren Twshp, Monroe Co., Ind. on the 1850 census. For info on Peter Thrasher check out the Thrasher family page on Genforum.
Here's the 1850 census.
1850 census Monroe County, Indiana, Van Buren Twnshp. pg. 10: Household 516: MICHAEL THRASHERmale43 (1807)Virginia MARGARETfemale43 (1807)Virginia HEASLET A.male19 (1831)Virginia TALBERT HORNELLmale19 (1831)Tennessee CATHERINE A.female17 (1833)Indiana MARY THRASHERfemale15 (1835)Indiana MARGARETfemale13 (1837)Indiana ORLEANAfemale11 (1839)Indiana SANFORDmale9 (1841)Indiana WILLIAM H.male7 (1843)Indiana