Robert married Susanna McCallum on 8 Feb 1855 in Roxborough, Ontario, Canada. Susanna (daughter of Duncan McCallum and Diana Montgomery) was born on 8 Jan 1833 in Strathmore, Roxborough, Stormont, Ontario, Canada; died on 8 Feb 1919 in Paisley, Bruce, Ontario, Canada. [Group Sheet] [Family Chart]

1. Alice Edna Begg was born on 16 Aug 1863 in Roxborough, Ontario, Canada; died on 1 Jan 1961 in Glen Ellyn, DuPage, Illinois, USA.
2. Alexander Duncan "Sandy" Begg was born on 22 Nov 1865 in Roxborough, Ontario, Canada; died in Nov 1953 in Pinkerton, , Ontario, Canada; was buried in Tiverton, Bruce, Ontario.
3. James Nelson Begg was born on 20 Apr 1869 in Tiverton, Bruce, Ontario; died on 14 May 1954.
4. Robert Stewart Begg was born on 18 Sep 1873 in Kincardine, Bruce, Ontario, Canada; died on 1 Jun 1949 in Detroit, Wayne, Michigan, USA; was buried in Dryden, , Ontario, Canada.