Robert married Mary Blake Wooddell on 25 Oct 1849 in , Pocahontas , West Virginia, United States. Mary (daughter of Joseph Wooddell and Delilah Arbogast) was born on 25 Jun 1831 in , Pocahontas , West Virginia, United States; died on 16 Dec 1906. [Group Sheet] [Family Chart]

1. Delilah Margaret Knapp was born on 26 Jul 1850; died on 17 Feb 1933 in , , Tucker Co., Wv.
2. George Benjamin Knapp was born on 2 Dec 1851; and died.
3. Lydia Ann Knapp was born on 28 Dec 1853; died on 18 Jan 1854.
4. Ira Ellis Knapp was born on 28 Dec 1854; died on 30 Apr 1873.
5. Frederick Asbury Knapp was born on 16 Jan 1857; died on 16 Nov 1859.
6. John Marshall Knapp was born on 24 Feb 1859; and died.
7. Bryson Columbus Knapp was born on 10 Dec 1860; died on 7 Nov 1862.
8. Elmira Frances Knapp was born on 15 Jan 1863 in , , Upshur Co., Va/Wv; died in 1947.
9. Elizabeth Jane Knapp was born on 10 Jun 1865; died on 9 Jul 1871.
10. Ida Emma Corena Knapp was born on 13 Oct 1867; and died.
11. Samantha Ellen Knapp was born on 24 Dec 1869; died on 13 Aug 1875.
12. Olive Christine Knapp was born on 22 Nov 1871; died on 15 Apr 1904.
13. Marietta Virginia Knapp was born on 25 Jun 1874 in , St. George, , Wv; and died.
14. Lorenzo Dow Knapp was born on 11 Nov 1879; and died.