Seth married Julia Resor 1861. Julia (daughter of William Resor, Sr. and Mary Thew Burnet) was born 16 Dec 1832, Cincinnati, Hamilton County, Ohio; died 25 Oct 1915, Cincinnati, Hamilton County, Ohio. [Group Sheet]

1. Mary Burnet Foster was born 6 Aug 1860; died 4 Sep 1918, Rome, Italy.
2. Julia Resor Foster was born 19 Dec 1862, Cincinnati, Hamilton County, Ohio; died 22 May 1937, Cincinnati, Hamilton County, Ohio.
3. Joseph Cutter Foster was born 6 Jun 1864, Cincinnati, Hamilton County, Ohio; died 25 Apr 1905, Cincinnati, Hamilton County, Ohio.
4. William Resor Foster was born 6 Jun 1864, Cincinnati, Hamilton County, Ohio; died 26 Jun 1925, Cincinnati, Hamilton County, Ohio.
5. Sallie Foster was born 18 Jul 1866.