In 1900 Della was recorded twice, once in Magoffin Co. with her mother and stepfather, and a week later in Morgan Co. with her mother’s parents, although with her age reported slightly differently:

1900 census of Magoffin Co., Ky, Bloomington precinct, enumerated 13 June, lists on p. 10B as family #169:
Howard, Cemore, 31, b. Oct 1868, Ky Ky --; Lillie, wife, 24, b. Feb 1876, Ky Ky Ky, married 4 years, mother of 3 children, 3 living; Ida, dau, 2, b. Nov 1897; Herbert, son, 1, b. Nov 1898; Ferguson, Della, stepdau, 8, b. Mar 1892. All children born Ky Ky Ky.

1900 census of Morgan Co., Ky, district 5, enumerated 19 June, lists on p. 20A as family #325:
Williams, Wallace, 52, b. Jan 1848; Manda M., wife, 26, b. Feb 1852; Pierce, son, 25, b. Mar 1875; Bruce, son, 19, b. May 1881; Emmie, dau, 17, b. Feb 1883; Grover C., son, 13, b. Mar 1887; Rachel A., dau, 11, b. May 1889; Fergerson, Della, granddau, 7, b. Apr 1893. All born Ky Ky Ky.

In 1910 she was recorded only once, in Morgan Co. with her mother’s brother Pierce, his wife, and her maternal grandfather:

1910 census of Morgan Co., Kentucky, Elk Fork precinct, lists as family #182/200:
Willams, Peral (male), 35, farmer; Sarah, wife, 24, first marriage for both, married 8 years, mother of 1 child, 1 living; Henry E., son, 2; Walas M., father, 62, widowed; Ferguson, Della, niece, 17, single. All born Ky Ky Ky.