This Isaac was the older brother of our ancestor Valentine "Felty" Yoakum who was born in 1785 and married to Charlotte Reynolds.

From Smith/Brown/Derryberry research we find "...Isaac Y. b. 23 Feb 1778, Muddy Creek, Greenbriar, WV, m. about 1800, Mary Davis, b. 1779, Powell Valley, Claiborne Co., TN, (daughter of Aaron Davis, (I) and Rachel _____) d. 1845. Isaac died 24 Jul 1857, Claiborne Co., TN, buried: Yoakum Cem., Black Valley Rd., Claib.. They are on 1850 census of Claiborne Co., TN, , house 1394."

...and from Lea Ann Yoakum of Powell Valley, who quotes the 1853 Will of Isaac,  we know Isaac and Marys' children are:
George Washington Y. b. 18 Aug 1802
Aaron Alvice Y. b. 1803.
John Y. b. 1806.
Moses Y. b. 21 Dec 1807.
Elizabeth b.1809.
Thomas Alvin b. 1813.
Marcillus 1815-1900.
William Franklin 1819-1900.