You didn't say which census you needed.
1880 census Denton Co, TX:
NameRelation Marital Status Gender Race Age Birthplace Occupation Father's Birthplace Mother's Birthplace
Bettie THOMASONWifeMFemaleW46KYHouse KeepingNCKY
If there's any doubt the above is the correct family, you will find them on the same page with just 2 families between them and Thomas Frier on 1870 census.
1870 census Denton Co, TX
Thomason, Wm H., 46, b TN
" Sarah E., 36, b KY
" John B., 8, b TX
" Mary J., 7, b TX
" George W., 3, b TX
1860 census Denton Co, TX:
Thomison(sic), W.H., 36, b TN - land 2400/personal 2000
" Sarah E., 26, b KY
1900 census Denton Co, TX, page 204:
Thomason, Jno, h, b Sep 1861, 38, M 15 yrs, b TX, AR, KY
" Leona, w, b Mar 1864, 36, M 15 yrs, 6 ch, 6 lvg, b TX, MO, AR
" Gertrude R., d, b Nov 1886, 13, b TX
" Nannie B., d, b Nov 188, 11, b TX
" Lela B., d, b Nov 1890, 9, b TX
" Hugh F., s, b Feb 1892, 8, b TX
" Myrtle D., d, b May 1895, 5, b TX
" Leona M., d, b Aug 1898, 1, b TX
" Zacharia M., uncle, b Aug 1828, 71, sgl, b AR, TN, TN
Thomason, Sarah E., h, b Jul 1834, 65 wid, b KY, NC, KY
Stapp, John G., boarder, b Mar 1854, 46, wid, b TX, MO, VA
" Maude, boarder, b Jun 188, 11
[I wonder if John Stapp might actually be a son-in-law, his wife might have been dau of Sarah's]
Page 205 brother George, with wife and family are listed.
Land and probate records might give a clue as to when William Henry Thomason died.He had quite a bit of land even when first married on the 1860 census.Denton Co, TX had a courthouse fire in mid 1870s, but land records are now available beginning with 1876, and W.H. was alive in 1880.
I can tell this is the same family, because on the 1860,70 and 1900 censuses one of their neighbors is Jeremiah Burnett, a brother to my husband's ancestor.
Do you need 1910 or 1920 censuses, too?
Happy Hunting (^_^)