On 6 May 1636, William Debnam was listed as a headright for Captain (later Colonel) Christopher Calthorpe of "Thropland."
William Debnam married Katherine (Unknown). They were the parents of four known children:
Kathrine (Debnam) (Taliaferro) Jones
Ann (Debnam) Hoyle
Mary (Debnam) Smith
William Debnam, Jr.
In the fall of 1648, William Debnam was one of four men ordered to appraise the estate of his neighbor Abraham Turner. Dednam had acquired land on Ware River in Mobjack Bay, Charles River (later Gloucester) County by 10 Oct 1642, when his property is mentioned as abutting a patent granted to Abraham Turner. He himself patented two parcels in Mobjack Bay ten years later: 600 acres on 6 May 1652 (one of the headright names listed is__Dickinson), and 1500 acres on 26 May 1653, both these patents were renewed, after his death, on 13 Jan 1661.
William Debnam, Sr. received a Mobjack Bay patent in 1652, totaling 2,100 acres.
William Debnam died in 1657 in Gloucester County.