Is it possible that your Silas Moffit is the son of James Moffit from the 1860 U.S. Census data of Amboy Township, Lee County, Illinois?
James Moffet age 60 (m.) born in Ireland; Ellenage 42 (f.) born in same
CHILDREN Jamesage 21 (m.) born in Ca.(California?); Samuel (m.)born in same; Thomasage 15 (m.) born in same; Margaret age 14 (f.) born in same
Mary age 11 (f.) born in ILLINOIS; Silas age 10 (m.) born in same; Eliza age 7 (f.) born in same; Lemuel age 5 (m.) born in same; Catherine age 4 (f.) born in same; Susan age 1 (f.) born in same.
I am very certain that this is the family of my line, based on the information we have concerning Eliza Moffit and a son known as Cyrus.The spellings in family records vary, but usually we see the surname as Moffat.
Our line is known to have lived in Illinois, Indiana, Iowa, and Nebraska.