My William was insistant that he was born in Tennessee, though I've seen Illinois here and there. I've also seen both Illinois and Tennessee for Martha. I've assigned that confusion to census-taker assumption. Birthdate, the best I have is his birth certificate's notation the he was 78 when he died in August of 1921. According to census response, he was born in April, which would put his birth year as 1843. I've seen a range of 1841-1843 listed in census records, and some of this early confusion may have been an attempt to make him seem older since he was on his own.
Is your Martha the one who married a Hendrckson? I was particularly interested in the fact that she named a daughter Lavina; according to William's death certificate, his mother was Lavina. I do think we might be tracking siblings, and I'd love to find out what happened to the mysterious "William and Lavina" mentioned as parents on William's death cert. I'm still going on the theory that William and Martha's father was a brother of Solomon Stegall, and I've yet to find another William who fits as the father of my William, yet I can find no evidence of marriage to anyone, much less "Lavina." Maybe we can collaborate and find the right trail.