It was the 1920 census, Hartford CN.
Horace M. Willey 36 Rent b. DE Father b. DE Mother b. DE
Cora Age 31 b. New York father b. NY, Mother b. NY
Etta (f) Age 7 b. Conn, Father b. DE, Mother b. NY
Alfred (m) Age 7 b. Conn, Father b. DE, Mother b. NY
Charles (m) Age 4 b. Conn, Father b. DE, Mother b. NY

The 1930 census shows No Horace but Cora is still living in Hartford on Liberty ST. HoH Age 41 md @20 and listed as married (not widowed)
Alfred P. 18, Charles C. 14, Horace A. 9 and Etta L. Cowles Rel- Dau. Age 19 md@16 and Albert H. Cowles Grandson Age 1. ANother Daughter is also listed Alice L. Simmons age 23 md@16. Finally a boarder- John L. McKenzie age 16

There is another Horace Willey listed in 1930 in Seaford, Married but no family info given but the age is off by about 6 years. (51 vs 46) That age doesn't match up with any of the Horace Willeys in previous censuses.