John was born about 1763, the son of unknown parents. The place is not known.
His wife was Ellison Jaap, who he married on 14 OCT 1787 in Glasgow. Their four known children were Thomas (1788-?), Andrew (1790-?), John (1792-?) and Margaret (1801-1871).
!Source: http://www.jaap.fsnet.co.uk/Webnew/Jaapwebnew.html The Jaap family tree. Entries: 2488, Updated: Sun Feb 29 09:17:00 2004, Contact: John Jaap