1840 Sycamore, Crawford Co, OH. That census recorded only one Jacob Combs and he and his wife were both 40-50 years old, too old to be this couple. However, as a young couple, Jacob and Sarah might have been living with them, if they were his parents.
Early 1850 CA If daughter Mary Jane was born in CA, they must have made a trip out west before she was born and then back east before census time in the fall.
10/2/1850 Dist 18, Madison Co, IA was where the next census taker found the family. Jacob was a 30 year old farmer with property valued at $1800. Sarah was 29 and their children at the time were: Barbara, 11, Ben Frank, 9, and Lucinda, 7.
6/19/1860 Madison, Madison Co, IA. He was probably at the same place by census time again. That year Jacob was 40, still farming and his estate had grown to $4000/500. It looks like he had remarried and had a blended family of his, hers, and theirs. His wife's name was Elizabeth, 33, with children: Ben F, 17, Sarah J, 14, Jacob G, 10, Isaac G, 5, George W, 4, Sarah A, 2, and Thomas J, 1.
6/21/1870 Wea, Miami Co, KS. Jacob was 50 years by the next census, Elizabeth was 43 and the family had increased to 10 children including two of Sarah's children, Jacob, 19 and Mary J Morrow, 19.