I am well acquainted with census records and what they show and don't show.
My William McCreary is allusive. He was born ca 1795-1800 in PA and probably moved to Licking Co., OHio with his parents and siblings in 1810. From there he disappears and I don't know a wife's name. There are several other William McCrearys in Knox Co but I don't know who their parents are. "Family stories" say William lived in Urbana, Champaign Co., OHio, then moved to Black Hawk Purchase in Illinois and then to Lee County, Iowa but I can't find him in any othese places so far.