Foster married Sarah Miranda Harris on 8 Dec 1859 in Jefferson, Tennessee, USA. Sarah (daughter of Crampton Smith Harris and Maria Jane McFarland) was born on 22 Jul 1838 in Jefferson County, Tennessee, United States of America; died on 29 Oct 1907 in Morristown, Hamblen County, Tennessee, United States of America; was buried in Hamblen County, Tennessee, United States of America. [Group Sheet] [Family Chart]

1. Effie Maria Whiteside was born on 14 Jan 1861; died on 19 Nov 1862.
2. Crampton Harris Whiteside was born on 15 Oct 1862 in Chattanooga, Hamilton County, Tennessee, United States of America; died in 1891 in Tennessee, United States of America.
3. Mary Elizabeth Whiteside was born on 15 Nov 1866 in Chattanooga, Hamilton, Tennessee, USA; died on 7 Dec 1944 in Hamblen, Tennessee, USA; was buried in Morristown, Hamblen County, Tennessee, United States of America.
4. Jennie Mariah Whitesides Douglass was born on 31 Oct 1869 in Chattanooga, Hamilton County, Tennessee, United States of America; died on 21 Dec 1903.
5. James A Whiteside was born in 1872 in Tennessee, United States of America; died in 1893 in Tennessee, United States of America.