William married Mary Jane Montgomery on 12 Oct 1865. Mary (daughter of John Montgomery and Elizabeth Brown) was born on 31 Jan 1844 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 11 May 1905; was buried in Gravel Hill, Stormont, Ontario, Ontario, Canada. [Group Sheet] [Family Chart]

1. John Wesley Johnstone was born on 31 Aug 1866 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 10 Mar 1891; was buried in Gravel Hill, Stormont, Ontario, Ontario, Canada.
2. Elizabeth Alice Johnstone was born on 1 Sep 1869 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 18 Jan 1946 in Monkland, Roxborough, Stormont, Ontario, Canada; was buried in Paul's Hill Cem, Avonmore, Stormont, Ontario, Canada.
3. Mary Isabella Johnstone was born on 9 Feb 1873 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 27 Apr 1958; was buried in Gravel Hill, Roxborough, Stormont, Ontario, Canada.
4. William Henry Johnstone was born on 12 Sep 1877 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 4 Mar 1955; was buried in Gravel Hill, Roxborough, Stormont, Ontario, Canada.
5. Louisa Adaline Johnston was born on 2 Nov 1879 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 4 Feb 1948 in Cornwall, Stormont, Ontario, Canada; was buried in Gravel Hill, Roxborough, Stormont, Ontario, Canada.
6. Ellen Janet Johnston was born on 19 Nov 1885 in Gravel Hill, Stormont, Ontario, Ontario, Canada; died on 14 Feb 1970 in Newington, Stormont, Ontario, Canada; was buried in Gravel Hill, Roxborough, Stormont, Ontario, Canada.