1850 census of Carter Co., Ky, district 1, enumerated 30 July, lists on p. 1 as family #3:
Low Brown, 55, farmer; Mary, 38; Julia A., 15; Mary E., 14; Cintha M., 11; Nancy L., 9; Sarah M., 7; James A., 4; Samuel H., 2; William A. Brown, 22, b. Va.

Low through Nancy born in Va, Sarah, James and Samuel born in Ky. William may be a son by a previous marriage or some other relationship, since he was listed after all the others and the surname repeated.

1860 census of Carter Co., Ky, Olive Hill P.O., enumerated 6 Aug, lists on p. 153 as family #1101/1009:
Low Brown, 62, farmer, b. Va; Mary, 48, b. Va; Sarah, 18; James, 16; Samuel H., 14; Flem L. 10; Mary, 7; Thomas L., 3. Sarah through Thomas born in Ky.

It seems unusual to name two daughters Mary when the first one lived to at least 14. Possibly one of them is really a niece.